Failure or imperfection of vision at night or in dim light, with good vision only on bright days. (Dorland, 27th ed)
The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.
Dryness of the eye surfaces caused by deficiency of tears or conjunctival secretions. It may be associated with vitamin A deficiency, trauma, or any condition in which the eyelids do not close completely.
Transmission of gene defects or chromosomal aberrations/abnormalities which are expressed in extreme variation in the structure or function of the eye. These may be evident at birth, but may be manifested later with progression of the disorder.
Recording of electric potentials in the retina after stimulation by light.
A nutritional condition produced by a deficiency of VITAMIN A in the diet, characterized by NIGHT BLINDNESS and other ocular manifestations such as dryness of the conjunctiva and later of the cornea (XEROPHTHALMIA). Vitamin A deficiency is a very common problem worldwide, particularly in developing countries as a consequence of famine or shortages of vitamin A-rich foods. In the United States it is found among the urban poor, the elderly, alcoholics, and patients with malabsorption. (From Cecil Textbook of Medicine, 19th ed, p1179)
Genetic diseases that are linked to gene mutations on the X CHROMOSOME in humans (X CHROMOSOME, HUMAN) or the X CHROMOSOME in other species. Included here are animal models of human X-linked diseases.
Adjustment of the eyes under conditions of low light. The sensitivity of the eye to light is increased during dark adaptation.
I'm sorry for any confusion, but "Nepal" is not a medical term that has a definition in the field of medicine. It is actually the name of a country located in South Asia, known officially as the Federal Democratic Republic of Nepal. If you have any questions related to medicine or health, I would be happy to try and help answer those for you!
Total loss of vision in all or part of the visual field due to bilateral OCCIPITAL LOBE (i.e., VISUAL CORTEX) damage or dysfunction. Anton syndrome is characterized by the psychic denial of true, organic cortical blindness. (Adams et al., Principles of Neurology, 6th ed, p460)
Hereditary, progressive degeneration of the neuroepithelium of the retina characterized by night blindness and progressive contraction of the visual field.
Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of CAROTENOIDS found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products.
A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.
Photosensitive afferent neurons located in the peripheral retina, with their density increases radially away from the FOVEA CENTRALIS. Being much more sensitive to light than the RETINAL CONE CELLS, the rod cells are responsible for twilight vision (at scotopic intensities) as well as peripheral vision, but provide no color discrimination.
A purplish-red, light-sensitive pigment found in RETINAL ROD CELLS of most vertebrates. It is a complex consisting of a molecule of ROD OPSIN and a molecule of 11-cis retinal (RETINALDEHYDE). Rhodopsin exhibits peak absorption wavelength at about 500 nm.
Institutional night care of patients.
Albinism affecting the eye in which pigment of the hair and skin is normal or only slightly diluted. The classic type is X-linked (Nettleship-Falls), but an autosomal recessive form also exists. Ocular abnormalities may include reduced pigmentation of the iris, nystagmus, photophobia, strabismus, and decreased visual acuity.
The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.
Retinal diseases refer to a diverse group of vision-threatening disorders that affect the retina's structure and function, including age-related macular degeneration, diabetic retinopathy, retinal detachment, retinitis pigmentosa, and macular edema, among others.
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.
INTERNEURONS of the vertebrate RETINA containing two processes. They receive inputs from the RETINAL PHOTORECEPTOR CELLS and send outputs to the RETINAL GANGLION CELLS. The bipolar cells also make lateral connections in the retina with the RETINAL HORIZONTAL CELLS and with the AMACRINE CELLS.
Vision considered to be inferior to normal vision as represented by accepted standards of acuity, field of vision, or motility. Low vision generally refers to visual disorders that are caused by diseases that cannot be corrected by refraction (e.g., MACULAR DEGENERATION; RETINITIS PIGMENTOSA; DIABETIC RETINOPATHY, etc.).
A retrogressive pathological change in the retina, focal or generalized, caused by genetic defects, inflammation, trauma, vascular disease, or aging. Degeneration affecting predominantly the macula lutea of the retina is MACULAR DEGENERATION. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p304)
The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)
Diseases affecting the eye.
Genes that influence the PHENOTYPE only in the homozygous state.
Photosensitive afferent neurons located primarily within the FOVEA CENTRALIS of the MACULA LUTEA. There are three major types of cone cells (red, blue, and green) whose photopigments have different spectral sensitivity curves. Retinal cone cells operate in daylight vision (at photopic intensities) providing color recognition and central visual acuity.
Filarial infection of the eyes transmitted from person to person by bites of Onchocerca volvulus-infected black flies. The microfilariae of Onchocerca are thus deposited beneath the skin. They migrate through various tissues including the eye. Those persons infected have impaired vision and up to 20% are blind. The incidence of eye lesions has been reported to be as high as 30% in Central America and parts of Africa.
The female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in human and other male-heterogametic species.
Conditions or pathological processes associated with pregnancy. They can occur during or after pregnancy, and range from minor discomforts to serious diseases that require medical interventions. They include diseases in pregnant females, and pregnancies in females with diseases.
Recording of the average amplitude of the resting potential arising between the cornea and the retina in light and dark adaptation as the eyes turn a standard distance to the right and the left. The increase in potential with light adaptation is used to evaluate the condition of the retinal pigment epithelium.
'Eye proteins' are structural or functional proteins, such as crystallins, opsins, and collagens, located in various parts of the eye, including the cornea, lens, retina, and aqueous humor, that contribute to maintaining transparency, refractive power, phototransduction, and overall integrity of the visual system.
Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.
A subgroup of TRP cation channels named after melastatin protein. They have the TRP domain but lack ANKYRIN repeats. Enzyme domains in the C-terminus leads to them being called chanzymes.
Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). (Dorland, 27th ed)
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A PROTEIN-SERINE-THREONINE KINASE that is found in PHOTORECEPTOR CELLS. It mediates light-dependent PHOSPHORYLATION of RHODOPSIN and plays an important role in PHOTOTRANSDUCTION.
A 48-Kd protein of the outer segment of the retinal rods and a component of the phototransduction cascade. Arrestin quenches G-protein activation by binding to phosphorylated photolyzed rhodopsin. Arrestin causes experimental autoimmune uveitis when injected into laboratory animals.
Specialized PHOTOTRANSDUCTION neurons in the vertebrates, such as the RETINAL ROD CELLS and the RETINAL CONE CELLS. Non-visual photoreceptor neurons have been reported in the deep brain, the PINEAL GLAND and organs of the circadian system.
The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.
Biochemical identification of mutational changes in a nucleotide sequence.
Persons with loss of vision such that there is an impact on activities of daily living.
A carotenoid that is a precursor of VITAMIN A. It is administered to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (PORPHYRIA, ERYTHROPOIETIC). (From Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Engewood, CO, 1995.)
The magnitude of INBREEDING in humans.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
The minimum amount of stimulus energy necessary to elicit a sensory response.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.
Long-lasting voltage-gated CALCIUM CHANNELS found in both excitable and nonexcitable tissue. They are responsible for normal myocardial and vascular smooth muscle contractility. Five subunits (alpha-1, alpha-2, beta, gamma, and delta) make up the L-type channel. The alpha-1 subunit is the binding site for calcium-based antagonists. Dihydropyridine-based calcium antagonists are used as markers for these binding sites.
A mutation in which a codon is mutated to one directing the incorporation of a different amino acid. This substitution may result in an inactive or unstable product. (From A Dictionary of Genetics, King & Stansfield, 5th ed)

Bothnia dystrophy caused by mutations in the cellular retinaldehyde-binding protein gene (RLBP1) on chromosome 15q26. (1/243)

PURPOSE: To determine the chromosomal location and to identify the gene causing a type of retinitis punctata albescens, called Bothnia dystrophy, found in a restricted geographic area in northern Sweden. METHODS: Twenty patients from seven families originating from a restricted geographic area in northern Sweden were clinically examined. Microsatellite markers were analyzed in all affected and unaffected family members. Direct genomic sequencing of the gene encoding cellular retinaldehyde-binding protein was performed after the linkage analysis had been completed. RESULTS: Affected individuals showed night blindness from early childhood with features consistent with retinitis punctata albescens and macular degeneration. The responsible gene was mapped to 15q26, the same region to which the cellular retinaldehyde-binding protein gene has been assigned. Subsequent analysis showed all affected patients were homozygous for a C to T substitution in exon 7 of the same gene, leading to the missense mutation Arg234Trp. Analysis of marker haplotypes suggested that all cases had a common ancestor who carried the mutation. CONCLUSIONS: A missense mutation in the cellular retinaldehyde-binding protein gene is the cause of Bothnia dystrophy. The disease is a local variant of retinitis punctata albescens that is common in northern Sweden due to a founder mutation.  (+info)

Recessive mutations in the RLBP1 gene encoding cellular retinaldehyde-binding protein in a form of retinitis punctata albescens. (2/243)

PURPOSE: To determine the frequency and spectrum of mutations in the RLBP1 gene encoding cellular retinaldehyde-binding protein (CRALBP) in patients with hereditary retinal degeneration. METHODS: The single-strand conformation polymorphism (SSCP) technique and a direct genomic sequencing technique were used to screen the coding exons of this gene (exons 2-8) for mutations in 324 unrelated patients with recessive or isolate retinitis pigmentosa, retinitis punctata albescens, Leber congenital amaurosis, or a related disease. Variant DNA fragments revealed by SSCP analysis were subsequently sequenced. Selected alleles that altered the coding region or intron splice sites were evaluated further through segregation analysis in the families of the index cases. RESULTS: Four novel mutations were identified in this gene among three unrelated patients with recessively inherited retinitis punctata albescens. Two of the mutations were missense: one was a frameshift, and one affected a canonical splice donor site. CONCLUSIONS: Recessive mutations in the RLBP1 gene are an uncommon cause of retinal degeneration in humans. The phenotype produced by RLBP1 mutations seems to be a form of retinitis punctata albescens.  (+info)

Phenotypic variations in a family with retinal dystrophy as result of different mutations in the ABCR gene. (3/243)

AIMS: To describe two phenotypic variations of autosomal recessive retinal dystrophy occurring in a consanguineous family in a pseudodominant pattern, resulting from mutations in the ATP binding cassette transporter (ABCR) gene. METHODS: Patients of this family underwent an extensive ophthalmic evaluation, including fundus photography, fluorescein angiography, and electroretinography (ERG). Genetic analysis comprised sequence analysis of the retina specific ABCR gene. RESULTS: Five patients presented with decreased visual acuity in the second decade, central chorioretinal atrophy associated with a central scotoma, and severely decreased photopic and scotopic ERG responses. This clinical picture, which in our opinion resembles a cone-rod dystrophy (CRD), was associated with compound heterozygosity for IVS30+ 1g -->t and IVS40+5g-->a mutations in the ABCR gene. The four remaining patients presented with night blindness in the first decade because of a retinitis pigmentosa-like (RP-like) dystrophy. In addition to a pale "waxy" optic disc, attenuated retinal vessels and bone spicule deposits, a widespread chorioretinal atrophy was observed. The scotopic ERG was extinguished and the photopic ERG was severely diminished. Genetic analysis revealed a homozygous 5' splice mutation IVS30+1g -->t in the ABCR gene. CONCLUSION: Mutations in the ABCR gene can cause clinical pictures resembling autosomal recessive RP and autosomal recessive CRD.  (+info)

Complete congenital stationary night blindness maps on Xp11.4 in a Sardinian family. (4/243)

X-linked congenital stationary night blindness (CSNBX) is a hereditary non-progressive retinal disorder, which can appear in two different clinical forms, complete and incomplete, associated with CSNB1 and CSNB2 loci on Xp. We describe a Sardinian family with complete CSNBX and define better the limits of the CSNB1 genetic locus on Xp11.4 through linkage analysis. Haplotype analysis showed two key recombinants, which restrict the CSNB1 locus to a region of about 3 cM limited by markers DSX1068 and DSX6810 respectively. The locus that we describe is included in the CSNB1 locus defined by previous reports referring to the same clinical form of the disease. These results, in addition to other recent mapping reports about families from different geographical areas, confirm the genetic homogeneity of X-linked complete CSNB.  (+info)

Difference between RP2 and RP3 phenotypes in X linked retinitis pigmentosa. (5/243)

AIM: X linked retinitis pigmentosa (XLRP) has two genetic loci known as "RP2" and "RP3". Clinical features reported to differentiate RP2 from RP3 include a higher prevalence of myopia and primary cone dysfunction in RP2, and late onset night blindness and tapetal reflex in RP3. Members from 14 XLRP families were examined in an attempt to verify these differences. METHODS: 16 affected males and 37 females from 14 XLRP families assigned as either RP2 or RP3 by haplotype analysis and/or by heterogeneity analysis were examined. Members of all 14 families who were willing to participate but unavailable for examination were contacted and detailed interviews carried out. RESULTS: No clear phenotypic differences were found that could be used to reliably differentiate RP2 from RP3 with respect to myopia and onset of night blindness. The tapetal reflex was also found to be present in carriers of both RP2 and RP3. CONCLUSIONS: XLRP is a heterogeneous class of rod degenerative disorders with no clear phenotypic differentiation between the two genetic loci RP2 and RP3. There is a continuum of clinical presentations which can be seen in both RP2 and RP3, but the features within a given family tend to be consistent. However, interfamilial variability is prevalent leading to a wide range of clinical presentations and more than one abnormal allele at each gene locus cannot be excluded.  (+info)

Localization of the mouse nob (no b-wave) gene to the centromeric region of the X chromosome. (6/243)

PURPOSE: To determine the position on the X chromosome of the gene responsible for a spontaneous mouse mutation, nob (no b-wave), which matches the phenotype of complete X-linked congenital stationary night blindness (CSNB) type 1 in human. METHODS: Inter- and intraspecific pedigrees were generated, and the phenotype of each mouse was scored on the basis of either the presence or the absence of an electroretinographic b-wave. DNA was isolated from a tail biopsy from each mouse and was used to determine the genotype at various polymorphic markers on the X chromosome. LOD scores (Z) between the nob phenotype and each marker were calculated to determine the most probable location of the nob gene. RESULTS: A total of 174 informative offspring were analyzed. The nob gene is tightly linked to DXMit103 with a maximum LOD score of 25.9 at a recombination fraction of zero. This marker is located at 4.2 cM on the X chromosome of the mouse map. Haplotype analyses of several recombinant chromosomes in the region indicates that the nob gene maps between DXMit54 (3.8 cM) and Ube1x (5.7 cM). CONCLUSIONS: The genetic position of the mouse nob gene overlaps the homologous region in human that contains the locus for CSNB1 and excludes the region of CSNB2. Further studies are planned to identify the mouse nob gene and to evaluate it as a candidate for CSNB1.  (+info)

Blue-on-yellow perimetry in the complete type of congenital stationary night blindness. (7/243)

PURPOSE: To resolve the discrepancy between nonrecordable full-field short wavelength cone electroretinograms (S-cone ERGs) and the presence of normal color vision in patients with the complete type of congenital stationary night blindness (CSNB1). METHODS: Conventional white-on-white (W-W) perimetry, blue-on-yellow (B-Y) perimetry, and the Farnsworth-Munsell 100-hue test were performed in five patients with CSNB1. Diagnosis of CSNB1 was made by clinical and electrophysiological examinations. Twelve normal, age-matched control subjects and an additional 7 normal, highly myopic subjects were tested. RESULTS: Color vision was normal in all the CSNB1 patients by the Farnsworth-Munsell 100-hue test. B-Y perimetry demonstrated that blue cone sensitivity in CSNB1 was normal in the fixation area, but the mean sensitivities of the entire 60 degrees field, the central 0 degrees-to-15 degrees, and 15 degrees-to-30 degrees ring were significantly decreased compared with the normal and myopic subjects. The sensitivity difference between 15 degrees-to-30 degrees and 0 degrees-to-15 degrees in B-Y perimetry increased significantly in CSNB1 compared with both normal and myopic control subjects. CONCLUSIONS: Our perimetric results demonstrated that the S-cone function in CSNB1 is preserved only in the fovea and becomes abnormal toward the peripheral retina. This accounts for the normal color vision that tests mainly foveal function and the nonrecordable S-cone ERGs that arise mainly from peripheral retina.  (+info)

Increased susceptibility to light damage in an arrestin knockout mouse model of Oguchi disease (stationary night blindness) (8/243)

PURPOSE: To determine whether constitutive signal flow arising from defective rhodopsin shut-off causes photoreceptor cell death in arrestin knockout mice. METHODS: The retinas of cyclic-light-reared, pigmented arrestin knockout mice and wild-type littermate control mice were examined histologically for photoreceptor cell loss from 100 days to 1 year of age. In separate experiments, to determine whether constant light would accelerate the degeneration in arrestin knockout mice, these animals and wild-type control mice were exposed for 1, 2, or 3 weeks to fluorescent light at an intensity of 115 to 150 fc. The degree of photoreceptor cell loss was quantified histologically by obtaining a mean outer nuclear layer thickness for each animal. RESULTS: In arrestin knockout mice maintained in cyclic light, photoreceptor loss was evident at 100 days of age, and it became progressively more severe, with less than 50% of photoreceptors surviving at 1 year of age. The photoreceptor degeneration appeared to be caused by light, because when these mice were reared in the dark, the retinal structure was indistinguishable from normal. When exposed to constant light, the retinas of wild-type pigmented mice showed no light-induced damage, regardless of exposure duration. By contrast, the retinas of arrestin knockout mice showed rapid degeneration in constant light, with a loss of 30% of photoreceptors after 1 week of exposure and greater than 60% after 3 weeks of exposure. CONCLUSIONS: The results indicate that constitutive signal flow due to arrestin knockout leads to photoreceptor degeneration. Excessive light accelerates the cell death process in pigmented arrestin knockout mice. Human patients with naturally occurring mutations that lead to nonfunctional arrestin and rhodopsin kinase have Oguchi disease, a form of stationary night blindness. The present findings suggest that such patients may be at greater risk of the damaging effects of light than those with other forms of retinal degeneration, and they provide an impetus to restrict excessive light exposure as a protective measure in patients with constitutive signal flow in phototransduction.  (+info)

Night blindness, also known as nyctalopia, is a visual impairment characterized by the inability to see well in low light or darkness. It's not an eye condition itself but rather a symptom of various underlying eye disorders, most commonly vitamin A deficiency and retinal diseases like retinitis pigmentosa.

In a healthy eye, a molecule called rhodopsin is present in the rods (special light-sensitive cells in our eyes responsible for vision in low light conditions). This rhodopsin requires sufficient amounts of vitamin A to function properly. When there's a deficiency of vitamin A or damage to the rods, the ability to see in dim light gets affected, leading to night blindness.

People with night blindness often have difficulty adjusting to changes in light levels, such as when entering a dark room from bright sunlight. They may also experience trouble seeing stars at night, driving at dusk or dawn, and navigating in poorly lit areas. If you suspect night blindness, it's essential to consult an eye care professional for proper diagnosis and treatment of the underlying cause.

Blindness is a condition of complete or near-complete vision loss. It can be caused by various factors such as eye diseases, injuries, or birth defects. Total blindness means that a person cannot see anything at all, while near-complete blindness refers to having only light perception or the ability to perceive the direction of light, but not able to discern shapes or forms. Legal blindness is a term used to define a certain level of visual impairment that qualifies an individual for government assistance and benefits; it usually means best corrected visual acuity of 20/200 or worse in the better eye, or a visual field no greater than 20 degrees in diameter.

Xerophthalmia is a medical condition characterized by dryness of the conjunctiva and cornea due to vitamin A deficiency. It can lead to eye damage, including night blindness (nyctalopia) and, if left untreated, potentially irreversible blindness. Xerophthalmia is often associated with malnutrition and affects children in low-income countries disproportionately.

Hereditary eye diseases refer to conditions that affect the eyes and are passed down from parents to their offspring through genetics. These diseases are caused by mutations or changes in an individual's DNA that are inherited from their parents. The mutations can occur in any of the genes associated with eye development, function, or health.

There are many different types of hereditary eye diseases, some of which include:

1. Retinitis Pigmentosa - a group of rare, genetic disorders that involve a breakdown and loss of cells in the retina.
2. Macular Degeneration - a progressive disease that damages the central portion of the retina, impairing vision.
3. Glaucoma - a group of eye conditions that damage the optic nerve, often caused by an increase in pressure inside the eye.
4. Cataracts - clouding of the lens inside the eye, which can lead to blurry vision and blindness.
5. Keratoconus - a progressive eye disease that causes the cornea to thin and bulge outward into a cone shape.
6. Color Blindness - a condition where an individual has difficulty distinguishing between certain colors.
7. Optic Neuropathy - damage to the optic nerve, which can result in vision loss.

The symptoms and severity of hereditary eye diseases can vary widely depending on the specific condition and the individual's genetic makeup. Some conditions may be present at birth or develop in early childhood, while others may not appear until later in life. Treatment options for these conditions may include medication, surgery, or lifestyle changes, and are often most effective when started early.

Electroretinography (ERG) is a medical test used to evaluate the functioning of the retina, which is the light-sensitive tissue located at the back of the eye. The test measures the electrical responses of the retina to light stimulation.

During the procedure, a special contact lens or electrode is placed on the surface of the eye to record the electrical activity generated by the retina's light-sensitive cells (rods and cones) and other cells in the retina. The test typically involves presenting different levels of flashes of light to the eye while the electrical responses are recorded.

The resulting ERG waveform provides information about the overall health and function of the retina, including the condition of the photoreceptors, the integrity of the inner retinal layers, and the health of the retinal ganglion cells. This test is often used to diagnose and monitor various retinal disorders, such as retinitis pigmentosa, macular degeneration, and diabetic retinopathy.

Vitamin A deficiency (VAD) is a condition that occurs when there is a lack of vitamin A in the diet. This essential fat-soluble vitamin plays crucial roles in vision, growth, cell division, reproduction, and immune system regulation.

In its severe form, VAD leads to xerophthalmia, which includes night blindness (nyctalopia) and keratomalacia - a sight-threatening condition characterized by dryness of the conjunctiva and cornea, with eventual ulceration and perforation. Other symptoms of VAD may include Bitot's spots (foamy, triangular, white spots on the conjunctiva), follicular hyperkeratosis (goose bump-like bumps on the skin), and increased susceptibility to infections due to impaired immune function.

Vitamin A deficiency is most prevalent in developing countries where diets are often low in animal source foods and high in plant-based foods with low bioavailability of vitamin A. It primarily affects children aged 6 months to 5 years, pregnant women, and lactating mothers. Prevention strategies include dietary diversification, food fortification, and supplementation programs.

X-linked genetic diseases refer to a group of disorders caused by mutations in genes located on the X chromosome. These conditions primarily affect males since they have only one X chromosome and therefore don't have a second normal copy of the gene to compensate for the mutated one. Females, who have two X chromosomes, are typically less affected because they usually have one normal copy of the gene on their other X chromosome.

Examples of X-linked genetic diseases include Duchenne and Becker muscular dystrophy, hemophilia A and B, color blindness, and fragile X syndrome. Symptoms and severity can vary widely depending on the specific condition and the nature of the genetic mutation involved. Treatment options depend on the particular disease but may include physical therapy, medication, or in some cases, gene therapy.

Dark adaptation is the process by which the eyes adjust to low levels of light. This process allows the eyes to become more sensitive to light and see better in the dark. It involves the dilation of the pupils, as well as chemical changes in the rods and cones (photoreceptor cells) of the retina. These changes allow the eye to detect even small amounts of light and improve visual acuity in low-light conditions. Dark adaptation typically takes several minutes to occur fully, but can be faster or slower depending on various factors such as age, prior exposure to light, and certain medical conditions. It is an important process for maintaining good vision in a variety of lighting conditions.

I'm sorry for any confusion, but "Nepal" is not a medical term. It is a country located in South Asia, between China and India. If you have any questions about medical terminology or health-related topics, I would be happy to try and help answer those for you.

Cortical blindness is a type of visual impairment that is caused by damage to the occipital cortex, which is the part of the brain responsible for processing visual information. This condition is also known as cerebral blindness or cerebral visual impairment.

In cortical blindness, the eyes are able to receive and transmit visual signals to the brain, but the brain is unable to interpret these signals correctly. As a result, the person may have difficulty recognizing objects, faces, or movements in their visual field. They may also experience hallucinations, such as seeing patterns or shapes that aren't really there.

Cortical blindness can be caused by a variety of factors, including stroke, trauma, brain tumors, infection, or hypoxia (lack of oxygen). In some cases, cortical blindness may be temporary and improve over time with treatment and rehabilitation. However, in other cases, the damage to the occipital cortex may be permanent, leading to a lifelong visual impairment.

It is important to note that cortical blindness is different from legal blindness, which is a term used to describe a severe visual impairment that cannot be corrected with glasses or contact lenses. In contrast, cortical blindness is a neurological condition that affects the brain's ability to process visual information, rather than a problem with the eyes themselves.

Retinitis pigmentosa (RP) is a group of rare, genetic disorders that involve a breakdown and loss of cells in the retina - a light-sensitive tissue located at the back of the eye. The retina converts light into electrical signals which are then sent to the brain and interpreted as visual images.

In RP, the cells that detect light (rods and cones) degenerate more slowly than other cells in the retina, leading to a progressive loss of vision. Symptoms typically begin in childhood with night blindness (difficulty seeing in low light), followed by a gradual narrowing of the visual field (tunnel vision). Over time, this can lead to significant vision loss and even blindness.

The condition is usually inherited and there are several different genes that have been associated with RP. The diagnosis is typically made based on a combination of genetic testing, family history, and clinical examination. Currently, there is no cure for RP, but researchers are actively working to develop new treatments that may help slow or stop the progression of the disease.

Medical Definition of Vitamin A:

Vitamin A is a fat-soluble vitamin that is essential for normal vision, immune function, and cell growth. It is also an antioxidant that helps protect the body's cells from damage caused by free radicals. Vitamin A can be found in two main forms: preformed vitamin A, which is found in animal products such as dairy, fish, and meat, particularly liver; and provitamin A carotenoids, which are found in plant-based foods such as fruits, vegetables, and vegetable oils.

The most active form of vitamin A is retinoic acid, which plays a critical role in the development and maintenance of the heart, lungs, kidneys, and other organs. Vitamin A deficiency can lead to night blindness, dry skin, and increased susceptibility to infections. Chronic vitamin A toxicity can cause nausea, dizziness, headaches, coma, and even death.

Myopia, also known as nearsightedness, is a common refractive error of the eye. It occurs when the eye is either too long or the cornea (the clear front part of the eye) is too curved. As a result, light rays focus in front of the retina instead of directly on it, causing distant objects to appear blurry while close objects remain clear.

Myopia typically develops during childhood and can progress gradually or rapidly until early adulthood. It can be corrected with glasses, contact lenses, or refractive surgery such as LASIK. Regular eye examinations are essential for people with myopia to monitor any changes in their prescription and ensure proper correction.

While myopia is generally not a serious condition, high levels of nearsightedness can increase the risk of certain eye diseases, including cataracts, glaucoma, retinal detachment, and myopic degeneration. Therefore, it's crucial to manage myopia effectively and maintain regular follow-ups with an eye care professional.

Retinal rod photoreceptor cells are specialized neurons in the retina of the eye that are primarily responsible for vision in low light conditions. They contain a light-sensitive pigment called rhodopsin, which undergoes a chemical change when struck by a single photon of light. This triggers a cascade of biochemical reactions that ultimately leads to the generation of electrical signals, which are then transmitted to the brain via the optic nerve.

Rod cells do not provide color vision or fine detail, but they allow us to detect motion and see in dim light. They are more sensitive to light than cone cells, which are responsible for color vision and detailed sight in bright light conditions. Rod cells are concentrated at the outer edges of the retina, forming a crescent-shaped region called the peripheral retina, with fewer rod cells located in the central region of the retina known as the fovea.

Rhodopsin, also known as visual purple, is a light-sensitive pigment found in the rods of the vertebrate retina. It is a complex protein molecule made up of two major components: an opsin protein and retinal, a form of vitamin A. When light hits the retinal in rhodopsin, it changes shape, which initiates a series of chemical reactions leading to the activation of the visual pathway and ultimately results in vision. This process is known as phototransduction. Rhodopsin plays a crucial role in low-light vision or scotopic vision.

'Night care' in a medical context typically refers to healthcare or support services provided to individuals during nighttime hours, usually between evening and early morning. This can include a range of services such as:

1. Monitoring vital signs and overall health status.
2. Administering medications.
3. Assisting with personal care needs like bathing, dressing, and using the bathroom.
4. Providing safety supervision to prevent falls or other accidents.
5. Offering comfort and companionship.

These services can be provided in various settings including hospitals, nursing homes, assisted living facilities, and private homes. They are often essential for individuals who require around-the-clock care but do not need hospital-level services during the night.

Ocular albinism is a type of albinism that primarily affects the eyes. It is a genetic disorder characterized by the reduction or absence of melanin, the pigment responsible for coloring the skin, hair, and eyes. In ocular albinism, melanin production is deficient in the eyes, leading to various eye abnormalities.

The main features of ocular albinism include:

1. Nystagmus: Rapid, involuntary back-and-forth movement of the eyes.
2. Iris transillumination: The iris appears translucent due to the lack of pigment, allowing light to pass through easily. This can be observed using a light source shone into the eye.
3. Foveal hypoplasia: Underdevelopment or absence of the fovea, a small pit in the retina responsible for sharp, central vision.
4. Photophobia: Increased sensitivity to light due to the lack of pigment in the eyes.
5. Strabismus: Misalignment of the eyes, which can result in double vision or lazy eye.
6. Reduced visual acuity: Decreased ability to see clearly, even with corrective lenses.

Ocular albinism is typically inherited as an X-linked recessive trait, meaning it primarily affects males, while females can be carriers of the condition. However, there are also autosomal recessive forms of ocular albinism that can affect both males and females equally. Treatment for ocular albinism usually involves managing symptoms with corrective lenses, low-vision aids, and vision therapy to improve visual skills.

I must clarify that the term "pedigree" is not typically used in medical definitions. Instead, it is often employed in genetics and breeding, where it refers to the recorded ancestry of an individual or a family, tracing the inheritance of specific traits or diseases. In human genetics, a pedigree can help illustrate the pattern of genetic inheritance in families over multiple generations. However, it is not a medical term with a specific clinical definition.

Retinal diseases refer to a group of conditions that affect the retina, which is the light-sensitive tissue located at the back of the eye. The retina is responsible for converting light into electrical signals that are sent to the brain and interpreted as visual images. Retinal diseases can cause vision loss or even blindness, depending on their severity and location in the retina.

Some common retinal diseases include:

1. Age-related macular degeneration (AMD): A progressive disease that affects the central part of the retina called the macula, causing blurred or distorted vision.
2. Diabetic retinopathy: A complication of diabetes that can damage the blood vessels in the retina, leading to vision loss.
3. Retinal detachment: A serious condition where the retina becomes separated from its underlying tissue, requiring immediate medical attention.
4. Macular edema: Swelling or thickening of the macula due to fluid accumulation, which can cause blurred vision.
5. Retinitis pigmentosa: A group of inherited eye disorders that affect the retina's ability to respond to light, causing progressive vision loss.
6. Macular hole: A small break in the macula that can cause distorted or blurry vision.
7. Retinal vein occlusion: Blockage of the retinal veins that can lead to bleeding, swelling, and potential vision loss.

Treatment for retinal diseases varies depending on the specific condition and its severity. Some treatments include medication, laser therapy, surgery, or a combination of these options. Regular eye exams are essential for early detection and treatment of retinal diseases.

The retina is the innermost, light-sensitive layer of tissue in the eye of many vertebrates and some cephalopods. It receives light that has been focused by the cornea and lens, converts it into neural signals, and sends these to the brain via the optic nerve. The retina contains several types of photoreceptor cells including rods (which handle vision in low light) and cones (which are active in bright light and are capable of color vision).

In medical terms, any pathological changes or diseases affecting the retinal structure and function can lead to visual impairment or blindness. Examples include age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinitis pigmentosa among others.

Visual acuity is a measure of the sharpness or clarity of vision. It is usually tested by reading an eye chart from a specific distance, such as 20 feet (6 meters). The standard eye chart used for this purpose is called the Snellen chart, which contains rows of letters that decrease in size as you read down the chart.

Visual acuity is typically expressed as a fraction, with the numerator representing the testing distance and the denominator indicating the smallest line of type that can be read clearly. For example, if a person can read the line on the eye chart that corresponds to a visual acuity of 20/20, it means they have normal vision at 20 feet. If their visual acuity is 20/40, it means they must be as close as 20 feet to see what someone with normal vision can see at 40 feet.

It's important to note that visual acuity is just one aspect of overall vision and does not necessarily reflect other important factors such as peripheral vision, depth perception, color vision, or contrast sensitivity.

Retinal bipolar cells are a type of neuron located in the inner nuclear layer of the retina, an light-sensitive tissue that lines the interior of the eye. These cells play a crucial role in the visual system by transmitting visual signals from photoreceptors (rods and cones) to ganglion cells, which then relay this information to the brain via the optic nerve.

Bipolar cells have two processes or "arms" that connect to either photoreceptors or ganglion cells: one process receives input from photoreceptors and the other transmits output to ganglion cells. They are called "bipolar" because of this dual connection. These cells can be classified into different types based on their morphology, neurotransmitter usage, and synaptic connections with photoreceptors and ganglion cells.

There are two primary types of retinal bipolar cells: rod bipolar cells and cone bipolar cells. Rod bipolar cells mainly transmit signals from rod photoreceptors, which are responsible for low-light vision, while cone bipolar cells connect to cone photoreceptors that handle color vision and high visual acuity in bright light conditions.

Retinal bipolar cells help process and encode visual information based on contrast, spatial patterns, and temporal changes in light intensity. Their output contributes significantly to the formation of visual perceptions such as brightness, contrast, and motion detection. Dysfunction or damage to retinal bipolar cells can lead to various visual impairments and diseases, including some forms of vision loss.

Low vision is a term used to describe significant visual impairment that cannot be corrected with standard glasses, contact lenses, medication or surgery. It is typically defined as visual acuity of less than 20/70 in the better-seeing eye after best correction, or a visual field of less than 20 degrees in the better-seeing eye.

People with low vision may have difficulty performing everyday tasks such as reading, recognizing faces, watching television, driving, or simply navigating their environment. They may also experience symptoms such as sensitivity to light, glare, or contrast, and may benefit from the use of visual aids, assistive devices, and rehabilitation services to help them maximize their remaining vision and maintain their independence.

Low vision can result from a variety of causes, including eye diseases such as macular degeneration, diabetic retinopathy, glaucoma, or cataracts, as well as congenital or inherited conditions, brain injuries, or aging. It is important for individuals with low vision to receive regular eye examinations and consult with a low vision specialist to determine the best course of treatment and management.

Retinal degeneration is a broad term that refers to the progressive loss of photoreceptor cells (rods and cones) in the retina, which are responsible for converting light into electrical signals that are sent to the brain. This process can lead to vision loss or blindness. There are many different types of retinal degeneration, including age-related macular degeneration, retinitis pigmentosa, and Stargardt's disease, among others. These conditions can have varying causes, such as genetic mutations, environmental factors, or a combination of both. Treatment options vary depending on the specific type and progression of the condition.

"Fundus Oculi" is a medical term that refers to the back part of the interior of the eye, including the optic disc, macula, fovea, retinal vasculature, and peripheral retina. It is the area where light is focused and then transmitted to the brain via the optic nerve, forming visual images. Examinations of the fundus oculi are crucial for detecting various eye conditions such as diabetic retinopathy, macular degeneration, glaucoma, and other retinal diseases. The examination is typically performed using an ophthalmoscope or a specialized camera called a retinal camera.

Eye diseases are a range of conditions that affect the eye or visual system, causing damage to vision and, in some cases, leading to blindness. These diseases can be categorized into various types, including:

1. Refractive errors: These include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, which affect the way light is focused on the retina and can usually be corrected with glasses or contact lenses.
2. Cataracts: A clouding of the lens inside the eye that leads to blurry vision, glare, and decreased contrast sensitivity. Cataract surgery is the most common treatment for this condition.
3. Glaucoma: A group of diseases characterized by increased pressure in the eye, leading to damage to the optic nerve and potential blindness if left untreated. Treatment includes medications, laser therapy, or surgery.
4. Age-related macular degeneration (AMD): A progressive condition that affects the central part of the retina called the macula, causing blurry vision and, in advanced stages, loss of central vision. Treatment may include anti-VEGF injections, laser therapy, or nutritional supplements.
5. Diabetic retinopathy: A complication of diabetes that affects the blood vessels in the retina, leading to bleeding, leakage, and potential blindness if left untreated. Treatment includes laser therapy, anti-VEGF injections, or surgery.
6. Retinal detachment: A separation of the retina from its underlying tissue, which can lead to vision loss if not treated promptly with surgery.
7. Amblyopia (lazy eye): A condition where one eye does not develop normal vision, often due to a misalignment or refractive error in childhood. Treatment includes correcting the underlying problem and encouraging the use of the weaker eye through patching or other methods.
8. Strabismus (crossed eyes): A misalignment of the eyes that can lead to amblyopia if not treated promptly with surgery, glasses, or other methods.
9. Corneal diseases: Conditions that affect the transparent outer layer of the eye, such as keratoconus, Fuchs' dystrophy, and infectious keratitis, which can lead to vision loss if not treated promptly.
10. Uveitis: Inflammation of the middle layer of the eye, which can cause vision loss if not treated promptly with anti-inflammatory medications or surgery.

Recessive genes refer to the alleles (versions of a gene) that will only be expressed when an individual has two copies of that particular allele, one inherited from each parent. If an individual inherits one recessive allele and one dominant allele for a particular gene, the dominant allele will be expressed and the recessive allele will have no effect on the individual's phenotype (observable traits).

Recessive genes can still play a role in determining an individual's genetic makeup and can be passed down through generations even if they are not expressed. If two carriers of a recessive gene have children, there is a 25% chance that their offspring will inherit two copies of the recessive allele and exhibit the associated recessive trait.

Examples of genetic disorders caused by recessive genes include cystic fibrosis, sickle cell anemia, and albinism.

Retinal cone photoreceptor cells are specialized neurons located in the retina of the eye, responsible for visual phototransduction and color vision. They are one of the two types of photoreceptors, with the other being rods, which are more sensitive to low light levels. Cones are primarily responsible for high-acuity, color vision during daylight or bright-light conditions.

There are three types of cone cells, each containing different photopigments that absorb light at distinct wavelengths: short (S), medium (M), and long (L) wavelengths, which correspond to blue, green, and red light, respectively. The combination of signals from these three types of cones allows the human visual system to perceive a wide range of colors and discriminate between them. Cones are densely packed in the central region of the retina, known as the fovea, which provides the highest visual acuity.

Onchocerciasis, Ocular is a medical condition that specifically refers to the eye manifestations caused by the parasitic infection, Onchocerca volvulus. Also known as "river blindness," this disease is spread through the bite of infected blackflies.

Ocular onchocerciasis affects various parts of the eye, including the conjunctiva, cornea, iris, and retina. The infection can cause symptoms such as itching, burning, and redness of the eyes. Over time, it may lead to more serious complications like punctate keratitis (small, scattered opacities on the cornea), cataracts, glaucoma, and ultimately, blindness.

The infection is diagnosed through a skin snip or blood test, which can detect the presence of microfilariae (the larval stage of the parasite) or antibodies against the parasite. Treatment typically involves administering oral medications such as ivermectin, which kills the microfilariae and reduces the risk of eye damage. However, it does not kill the adult worms, so multiple doses are often required to control the infection. In some cases, surgery may be necessary to remove advanced ocular lesions.

The X chromosome is one of the two types of sex-determining chromosomes in humans (the other being the Y chromosome). It's one of the 23 pairs of chromosomes that make up a person's genetic material. Females typically have two copies of the X chromosome (XX), while males usually have one X and one Y chromosome (XY).

The X chromosome contains hundreds of genes that are responsible for the production of various proteins, many of which are essential for normal bodily functions. Some of the critical roles of the X chromosome include:

1. Sex Determination: The presence or absence of the Y chromosome determines whether an individual is male or female. If there is no Y chromosome, the individual will typically develop as a female.
2. Genetic Disorders: Since females have two copies of the X chromosome, they are less likely to be affected by X-linked genetic disorders than males. Males, having only one X chromosome, will express any recessive X-linked traits they inherit.
3. Dosage Compensation: To compensate for the difference in gene dosage between males and females, a process called X-inactivation occurs during female embryonic development. One of the two X chromosomes is randomly inactivated in each cell, resulting in a single functional copy per cell.

The X chromosome plays a crucial role in human genetics and development, contributing to various traits and characteristics, including sex determination and dosage compensation.

Pregnancy complications refer to any health problems that arise during pregnancy which can put both the mother and the baby at risk. These complications may occur at any point during the pregnancy, from conception until childbirth. Some common pregnancy complications include:

1. Gestational diabetes: a type of diabetes that develops during pregnancy in women who did not have diabetes before becoming pregnant.
2. Preeclampsia: a pregnancy complication characterized by high blood pressure and damage to organs such as the liver or kidneys.
3. Placenta previa: a condition where the placenta covers the cervix, which can cause bleeding and may require delivery via cesarean section.
4. Preterm labor: when labor begins before 37 weeks of gestation, which can lead to premature birth and other complications.
5. Intrauterine growth restriction (IUGR): a condition where the fetus does not grow at a normal rate inside the womb.
6. Multiple pregnancies: carrying more than one baby, such as twins or triplets, which can increase the risk of premature labor and other complications.
7. Rh incompatibility: a condition where the mother's blood type is different from the baby's, which can cause anemia and jaundice in the newborn.
8. Pregnancy loss: including miscarriage, stillbirth, or ectopic pregnancy, which can be emotionally devastating for the parents.

It is important to monitor pregnancy closely and seek medical attention promptly if any concerning symptoms arise. With proper care and management, many pregnancy complications can be treated effectively, reducing the risk of harm to both the mother and the baby.

Electrooculography (EOG) is a technique for measuring the resting potential of the eye and the changes in this potential that occur with eye movements. It involves placing electrodes near the eyes to detect the small electric fields generated by the movement of the eyeball within the surrounding socket. This technique is used in research and clinical settings to study eye movements and their control, as well as in certain diagnostic applications such as assessing the function of the oculomotor system in patients with neurological disorders.

Eye proteins, also known as ocular proteins, are specific proteins that are found within the eye and play crucial roles in maintaining proper eye function and health. These proteins can be found in various parts of the eye, including the cornea, iris, lens, retina, and other structures. They perform a wide range of functions, such as:

1. Structural support: Proteins like collagen and elastin provide strength and flexibility to the eye's tissues, enabling them to maintain their shape and withstand mechanical stress.
2. Light absorption and transmission: Proteins like opsins and crystallins are involved in capturing and transmitting light signals within the eye, which is essential for vision.
3. Protection against damage: Some eye proteins, such as antioxidant enzymes and heat shock proteins, help protect the eye from oxidative stress, UV radiation, and other environmental factors that can cause damage.
4. Regulation of eye growth and development: Various growth factors and signaling molecules, which are protein-based, contribute to the proper growth, differentiation, and maintenance of eye tissues during embryonic development and throughout adulthood.
5. Immune defense: Proteins involved in the immune response, such as complement components and immunoglobulins, help protect the eye from infection and inflammation.
6. Maintenance of transparency: Crystallin proteins in the lens maintain its transparency, allowing light to pass through unobstructed for clear vision.
7. Neuroprotection: Certain eye proteins, like brain-derived neurotrophic factor (BDNF), support the survival and function of neurons within the retina, helping to preserve vision.

Dysfunction or damage to these eye proteins can contribute to various eye disorders and diseases, such as cataracts, age-related macular degeneration, glaucoma, diabetic retinopathy, and others.

Photoreceptor cells are specialized neurons in the retina of the eye that convert light into electrical signals. These cells consist of two types: rods and cones. Rods are responsible for vision at low light levels and provide black-and-white, peripheral, and motion sensitivity. Cones are active at higher light levels and are capable of color discrimination and fine detail vision. Both types of photoreceptor cells contain light-sensitive pigments that undergo chemical changes when exposed to light, triggering a series of electrical signals that ultimately reach the brain and contribute to visual perception.

Transient Receptor Potential Melastatin (TRPM) cation channels are a subfamily of the transient receptor potential (TRP) channel superfamily, which are non-selective cation channels that play important roles in various cellular processes such as sensory perception, cell proliferation, and migration.

The TRPM subfamily consists of eight members (TRPM1-8), each with distinct functional properties and expression patterns. These channels are permeable to both monovalent and divalent cations, including calcium (Ca^2+^) and magnesium (Mg^2+^).

TRPM channels can be activated by a variety of stimuli, such as changes in temperature, voltage, osmolarity, and chemical ligands. For example, TRPM8 is known to be activated by cold temperatures and menthol, while TRPV1 is activated by heat and capsaicin.

Dysregulation of TRPM channels has been implicated in various pathological conditions, including pain, neurodegenerative diseases, and cancer. Therefore, understanding the structure and function of these channels may provide insights into potential therapeutic targets for these conditions.

A cataract is a clouding of the natural lens in the eye that affects vision. This clouding can cause vision to become blurry, faded, or dim, making it difficult to see clearly. Cataracts are a common age-related condition, but they can also be caused by injury, disease, or medication use. In most cases, cataracts develop gradually over time and can be treated with surgery to remove the cloudy lens and replace it with an artificial one.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

G-Protein-Coupled Receptor Kinase 1 (GRK1) is a serine/threonine kinase that specifically phosphorylates and desensitizes G-protein-coupled receptors (GPCRs) upon agonist activation. GRK1 plays a crucial role in the regulation of GPCR signaling, which is involved in various physiological processes, including sensory perception, neurotransmission, and hormonal regulation.

GRK1 is primarily expressed in the retina and testis, where it regulates the activity of rhodopsin and β-adrenergic receptors, respectively. The kinase activity of GRK1 leads to the recruitment of arrestin proteins, which uncouple the receptor from its G protein, thereby terminating the signaling response. Additionally, GRK1-mediated phosphorylation creates binding sites for β-arrestins, leading to receptor internalization and subsequent degradation or recycling.

Mutations in GRK1 have been associated with various diseases, including retinitis pigmentosa, a genetic disorder that causes progressive vision loss. Therefore, understanding the function and regulation of GRK1 is essential for developing therapeutic strategies targeting GPCR-mediated diseases.

Arrestin is a type of protein that plays a crucial role in regulating the signaling of G protein-coupled receptors (GPCRs) in cells. These receptors are involved in various cellular responses to hormones, neurotransmitters, and other signaling molecules.

When a signaling molecule binds to a GPCR, it activates the receptor and triggers a cascade of intracellular events, including the activation of G proteins. Arrestin binds to the activated GPCR and prevents further interaction with G proteins, effectively turning off the signal.

There are two main types of arrestins: visual arrestin (or rod arrestin) and non-visual arrestins (which include β-arrestin1 and β-arrestin2). Visual arrestin is primarily found in the retina and plays a role in regulating the light-sensitive proteins rhodopsin and cone opsin. Non-visual arrestins, on the other hand, are expressed throughout the body and regulate various GPCRs involved in diverse physiological processes such as cell growth, differentiation, and migration.

By modulating GPCR signaling, arrestins help maintain proper cellular function and prevent overactivation of signaling pathways that could lead to disease. Dysregulation of arrestin function has been implicated in various pathologies, including cancer, cardiovascular diseases, and neurological disorders.

Photoreceptor cells in vertebrates are specialized types of neurons located in the retina of the eye that are responsible for converting light stimuli into electrical signals. These cells are primarily responsible for the initial process of vision and have two main types: rods and cones.

Rods are more numerous and are responsible for low-light vision or scotopic vision, enabling us to see in dimly lit conditions. They do not contribute to color vision but provide information about the shape and movement of objects.

Cones, on the other hand, are less numerous and are responsible for color vision and high-acuity vision or photopic vision. There are three types of cones, each sensitive to different wavelengths of light: short (S), medium (M), and long (L) wavelengths, which correspond to blue, green, and red, respectively. The combination of signals from these three types of cones allows us to perceive a wide range of colors.

Both rods and cones contain photopigments that consist of a protein called opsin and a light-sensitive chromophore called retinal. When light hits the photopigment, it triggers a series of chemical reactions that ultimately lead to the generation of an electrical signal that is transmitted to the brain via the optic nerve. This process enables us to see and perceive our visual world.

Genetic linkage is the phenomenon where two or more genetic loci (locations on a chromosome) tend to be inherited together because they are close to each other on the same chromosome. This occurs during the process of sexual reproduction, where homologous chromosomes pair up and exchange genetic material through a process called crossing over.

The closer two loci are to each other on a chromosome, the lower the probability that they will be separated by a crossover event. As a result, they are more likely to be inherited together and are said to be linked. The degree of linkage between two loci can be measured by their recombination frequency, which is the percentage of meiotic events in which a crossover occurs between them.

Linkage analysis is an important tool in genetic research, as it allows researchers to identify and map genes that are associated with specific traits or diseases. By analyzing patterns of linkage between markers (identifiable DNA sequences) and phenotypes (observable traits), researchers can infer the location of genes that contribute to those traits or diseases on chromosomes.

DNA Mutational Analysis is a laboratory test used to identify genetic variations or changes (mutations) in the DNA sequence of a gene. This type of analysis can be used to diagnose genetic disorders, predict the risk of developing certain diseases, determine the most effective treatment for cancer, or assess the likelihood of passing on an inherited condition to offspring.

The test involves extracting DNA from a patient's sample (such as blood, saliva, or tissue), amplifying specific regions of interest using polymerase chain reaction (PCR), and then sequencing those regions to determine the precise order of nucleotide bases in the DNA molecule. The resulting sequence is then compared to reference sequences to identify any variations or mutations that may be present.

DNA Mutational Analysis can detect a wide range of genetic changes, including single-nucleotide polymorphisms (SNPs), insertions, deletions, duplications, and rearrangements. The test is often used in conjunction with other diagnostic tests and clinical evaluations to provide a comprehensive assessment of a patient's genetic profile.

It is important to note that not all mutations are pathogenic or associated with disease, and the interpretation of DNA Mutational Analysis results requires careful consideration of the patient's medical history, family history, and other relevant factors.

Medical definitions for visual impairment often vary, but according to the World Health Organization (WHO), visually impaired persons are those who have a best-corrected visual acuity of less than 0.3 (6/12) in their better eye or a visual field of less than 20 degrees in their better eye. This includes people who are blind, as well as those with partial sight.

Visual impairment can range from mild to severe and may result from a variety of causes, including genetic disorders, diseases, trauma, or aging. It is important to note that visual impairment does not necessarily mean total blindness; many visually impaired individuals have some remaining vision and can benefit from low vision services and assistive devices.

Beta-carotene is a type of carotenoid, which is a pigment found in plants that gives them their vibrant colors. It is commonly found in fruits and vegetables, such as carrots, sweet potatoes, and spinach.

Beta-carotene is converted into vitamin A in the body, which is an essential nutrient for maintaining healthy vision, immune function, and cell growth. It acts as an antioxidant, helping to protect cells from damage caused by free radicals.

According to the medical definition, beta-carotene is a provitamin A carotenoid that is converted into vitamin A in the body. It has a variety of health benefits, including supporting eye health, boosting the immune system, and reducing the risk of certain types of cancer. However, it is important to note that excessive consumption of beta-carotene supplements can lead to a condition called carotenemia, which causes the skin to turn yellow or orange.

Consanguinity is a medical and genetic term that refers to the degree of genetic relationship between two individuals who share common ancestors. Consanguineous relationships exist when people are related by blood, through a common ancestor or siblings who have children together. The closer the relationship between the two individuals, the higher the degree of consanguinity.

The degree of consanguinity is typically expressed as a percentage or fraction, with higher values indicating a closer genetic relationship. For example, first-degree relatives, such as parents and children or full siblings, share approximately 50% of their genes and have a consanguinity coefficient of 0.25 (or 25%).

Consanguinity can increase the risk of certain genetic disorders and birth defects in offspring due to the increased likelihood of sharing harmful recessive genes. The risks depend on the degree of consanguinity, with closer relationships carrying higher risks. It is important for individuals who are planning to have children and have a history of consanguinity to consider genetic counseling and testing to assess their risk of passing on genetic disorders.

Ocular vision refers to the ability to process and interpret visual information that is received by the eyes. This includes the ability to see clearly and make sense of the shapes, colors, and movements of objects in the environment. The ocular system, which includes the eye and related structures such as the optic nerve and visual cortex of the brain, works together to enable vision.

There are several components of ocular vision, including:

* Visual acuity: the clarity or sharpness of vision
* Field of vision: the extent of the visual world that is visible at any given moment
* Color vision: the ability to distinguish different colors
* Depth perception: the ability to judge the distance of objects in three-dimensional space
* Contrast sensitivity: the ability to distinguish an object from its background based on differences in contrast

Disorders of ocular vision can include refractive errors such as nearsightedness or farsightedness, as well as more serious conditions such as cataracts, glaucoma, and macular degeneration. These conditions can affect one or more aspects of ocular vision and may require medical treatment to prevent further vision loss.

Sensory thresholds are the minimum levels of stimulation that are required to produce a sensation in an individual, as determined through psychophysical testing. These tests measure the point at which a person can just barely detect the presence of a stimulus, such as a sound, light, touch, or smell.

There are two types of sensory thresholds: absolute and difference. Absolute threshold is the minimum level of intensity required to detect a stimulus 50% of the time. Difference threshold, also known as just noticeable difference (JND), is the smallest change in intensity that can be detected between two stimuli.

Sensory thresholds can vary between individuals and are influenced by factors such as age, attention, motivation, and expectations. They are often used in clinical settings to assess sensory function and diagnose conditions such as hearing or vision loss.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

A circadian rhythm is a roughly 24-hour biological cycle that regulates various physiological and behavioral processes in living organisms. It is driven by the body's internal clock, which is primarily located in the suprachiasmatic nucleus (SCN) of the hypothalamus in the brain.

The circadian rhythm controls many aspects of human physiology, including sleep-wake cycles, hormone secretion, body temperature, and metabolism. It helps to synchronize these processes with the external environment, particularly the day-night cycle caused by the rotation of the Earth.

Disruptions to the circadian rhythm can have negative effects on health, leading to conditions such as insomnia, sleep disorders, depression, bipolar disorder, and even increased risk of chronic diseases like cancer, diabetes, and cardiovascular disease. Factors that can disrupt the circadian rhythm include shift work, jet lag, irregular sleep schedules, and exposure to artificial light at night.

Calcium channels, L-type, are a type of voltage-gated calcium channel that are widely expressed in many excitable cells, including cardiac and skeletal muscle cells, as well as certain neurons. These channels play a crucial role in the regulation of various cellular functions, such as excitation-contraction coupling, hormone secretion, and gene expression.

L-type calcium channels are composed of five subunits: alpha-1, alpha-2, beta, gamma, and delta. The alpha-1 subunit is the pore-forming subunit that contains the voltage sensor and the selectivity filter for calcium ions. It has four repeated domains (I-IV), each containing six transmembrane segments (S1-S6). The S4 segment in each domain functions as a voltage sensor, moving outward upon membrane depolarization to open the channel and allow calcium ions to flow into the cell.

L-type calcium channels are activated by membrane depolarization and have a relatively slow activation and inactivation time course. They are also modulated by various intracellular signaling molecules, such as protein kinases and G proteins. L-type calcium channel blockers, such as nifedipine and verapamil, are commonly used in the treatment of hypertension, angina, and certain cardiac arrhythmias.

A missense mutation is a type of point mutation in which a single nucleotide change results in the substitution of a different amino acid in the protein that is encoded by the affected gene. This occurs when the altered codon (a sequence of three nucleotides that corresponds to a specific amino acid) specifies a different amino acid than the original one. The function and/or stability of the resulting protein may be affected, depending on the type and location of the missense mutation. Missense mutations can have various effects, ranging from benign to severe, depending on the importance of the changed amino acid for the protein's structure or function.

... (CSNB) is a rare non-progressive retinal disorder. People with CSNB often have difficulty ... The complete form of X-linked congenital stationary night blindness, also known as nyctalopia, is caused by mutations in the ... "Congenital Stationary Night Blindness (CSNB2) in Tennessee Walking Horses , Veterinary Genetics Laboratory". vgl.ucdavis.edu. ... The incomplete form of X-linked congenital stationary night blindness (CSNB2) is caused by mutations in the CACNA1F gene, which ...
Night Blindness Chat; Lynx (December 31, 1988) Horse Jumping; Toys In Space; Dust Bunnies; Carnivorous Plants; "Lemons"; Toucan ... Color Blindness; Taste Buds; Black Hole Chat (November 26, 1983) Digital Sound; Eggs; Teeth Chatter Chat; Camel (December 3, ...
... blindness can result. This is night-blindness. Rods make use of three inhibitory mechanisms (negative feedback mechanisms) to ... "Loss of the Effector Function in a Transducin-α Mutant Associated with Nougaret Night Blindness". J. Biol. Chem. 275 (10): 6969 ... Rod cells are more sensitive than cone cells and are almost entirely responsible for night vision. However, rods have little ... Since rods require less light to function than cones, they are the primary source of visual information at night (scotopic ...
Some Tennessee Walking Horses may be affected by the following genetic conditions: Congenital Stationary Night Blindness (CSNB2 ... Young, Amy (June 8, 2020). "Congenital Stationary Night Blindness (CSNB)". School of Veterinary Medicine. Retrieved May 24, ... genome sequencing identifies missense mutation in GRM6 as the likely cause of congenital stationary night blindness in a ... Horses may also be reluctant to move at night and may struggle to find food and water. It is a non-progressive condition that ...
"Night Blindness in the Appaloosa (CSNB)". The Appaloosa Project. 15 November 2013. Retrieved 2017-09-01. Oke, Stacey (August 31 ... Horses homozygous for the Lp gene are also at risk for congenital stationary night blindness (CSNB). Studies in 2008 and 2010 ... and congenital stationary night blindness (CSNB) in horses". Animal Genetics. 41 (s2): 207. doi:10.1111/j.1365-2052.2010.02119. ... "Shedding Light on Night Blindness in Appaloosas". The Horse. Retrieved February 7, 2009. Bellone, R.; Archer, S.; Wade, C. M.; ...
CABP4 Night blindness, congenital stationary, type IC; 613216; TRPM1 Night blindness, congenital stationary, X-linked, type 2A ... CSNB1 Night blindness, congenital stationary, type 1B; 257270; GRM6 Night blindness, congenital stationary, type 2B; 610427; ... PDE6B Night blindness, congenital stationary, autosomal dominant 3; 610444; GNAT1 Night blindness, congenital stationary, type ... CACNA1F Night blindness, congenital stationary, autosomal dominant 1; 610445; RHO Nijmegen breakage syndrome; 251260; NBS1 ...
... loss of peripheral vision often results in night blindness. Individuals with night blindness not only see poorly at night but ... night blindness was viewed as a condition that could be easily faked or exaggerated, and initially, people with night blindness ... Another cause of night blindness is a deficiency of retinol, or vitamin A1, found in fish oils, liver and dairy products. The ... Night blindness may exist from birth, or be caused by injury or malnutrition (for example, vitamin A deficiency). It can be ...
... a Pole suffering from night blindness; and Zoran, a Yugoslav accountant. Khabarov secretly tells Janusz that he is planning to ... a young Polish inmate suffering from night blindness Mark Strong as Andrei Timofeyevich Khabarov, a Russian inmate and actor ... Kazik freezes to death the second night of the trek, after losing his way back to the campsite while looking for wood, and the ...
Vitamin A deficiency can induce night blindness. Calcium oxalate renal stones occur commonly following JIB, along with ...
Congenital stationary night blindness is an ophthalmologic disorder in horses which is present at birth (congenital), non- ... Electroretinography of congenital night blindness in an Appaloosa filly. Journal of Equine Medicine and Surgery 1977; 1: 226- ... 2013). "Evidence for a Retroviral Insertion in TRPM1 as the Cause of Congenital Stationary Night Blindness and Leopard Complex ... August 2008). "Differential Gene Expression of TRPM1, the Potential Cause of Congenital Stationary Night Blindness and Coat ...
LCA therefore manifests as nyctalopia (night blindness). In the later stages of the disease, general retinopathy is observed as ...
... gene are also at risk for congenital stationary night blindness (CSNB). This form of night blindness has been linked with the ... "Night Blindness in the Appaloosa (CSNB)". The Appaloosa Project. Archived from the original on July 7, 2011. Retrieved December ... Witzel, C.A.; Joyce, J.R.; Smith, E.L. (1977). "Electroretinography of congenital night blindness in an Appaloosa filly". ... Oke, Stacey (August 31, 2008). "Shedding Light on Night Blindness in Appaloosas". The Horse. Retrieved February 7, 2009. "2012 ...
... night-blindness) involves him in a series of difficult situations. Marianela is an 1878 Spanish novel by Benito Pérez Galdós, ... Blindness, a 1995 Portuguese novel by José Saramago, depicts the social breakdown which follows an epidemic of blindness. The ... Hartsock, Chad (2008). Sight and Blindness in Luke-Acts. Brill. Jernigan, Kenneth (1974). "Blindness: Is Literature Against Us ... Notes on Blindness is a 2016 documentary film about John M. Hull, blind theologian and author of Touching the Rock: An ...
The night blindness develops progressively into complete blindness. The British institution Animal Health Trust (AHT) devoted ... The earliest clinical sign of progressive retinal atrophy is "night blindness." The dog cannot see well in a dimly lit room or ... They also slept with the monks at night to provide warmth. Village-bred Tibetan Spaniels varied greatly in size and type, and ... The disease is an inherited form of blindness in dogs that has in two forms: generalized PRA and central PRA. Generalized PRA ...
Lem J, Fain GL (2004). "Constitutive opsin signaling: night blindness or retinal degeneration?". Trends Mol Med. 10 (4): 150- ... night blindness, retinal detachment, light sensitivity, tunnel vision, and loss of peripheral vision to total loss of vision. ... A prominent early clinical feature of retinitis pigmentosa is the loss of night vision as a result of death of rod ... Irreversible loss of these cells has been attributed as a cause of blindness in many retinal degenerative disorders, including ...
Individuals with this condition usually start showing signs of nyctalopia (also known as night-blindness) during their early ... He was said to have difficulties walking inside his mother's apartment as soon as night fell from childhood (nightblindness), ... and nightblindness. If they remain un-treated, they can end up in severe vision impairment. Goldmann-Favre syndrome patients ...
"Color-Blindness in Foulk Woods". Evening Journal. October 1, 1963 - via Newspapers.com. (CS1 maint: multiple names: authors ... "Faulk Woods Victor". Journal-Every Evening. May 20, 1959 - via Newspapers.com. "Foulk Woods Winner". Journal-Every Evening. ... "Baseball Standings". Evening Journal. June 17, 1967 - via Newspapers.com. Foulk Woods Civic Association on Facebook "Hear Ye! ...
The first symptom of the disease is night blindness. Blindness and neurological signs such as epilepsy, motor abnormalities, ...
Defects in GRK1 result in Oguchi stationary night blindness. GRK7 similarly regulates cone opsin phosphorylation and ...
Night blindness may be seen in patients with KSS. Visual acuity loss is usually mild and only occurs in 40-50% of patients. ... night vision abnormalities, and some histologic similarities, but also clinical differences, to retinitis pigmentosa ...
... is a film about night blindness". deccanherald.com. 6 April 2018. "'Andhagaara' is a film about night blindness - Deccan Herald ... who turns visually impaired at night. The story starts with Raghu who happens to receive a large amount of black money from his ...
A lack of vitamin A can cause night blindness; a study in 2005 showed that 348 pregnant Nepali women who ate Ultra Rice had ... "Recovery from impaired dark adaptation in night-blind pregnant Nepali women who receive small daily doses of vitamin A as ... improvement in night vision which did not different significantly from the improvement which could come from vitamin A as liver ...
As a result of night-blindness, he bungles every step. When he has a bath, instead of clean water, he pours a pot of animals' ... Jivram gets up at midnight to use the bathroom; however, to avoid getting lost due to his night-blindness, he ties his turban ... The play tells a story of Jivaram Bhatt, who suffers from nyctalopia (night blindness) but does not want people to know about ... However, because he suffers from nyctalopia (night blindness), he cannot decide which way to go. He conceals his disability by ...
This causes night blindness at first and eventually complete blindness. Collie eye anomaly is estimated to have a carrier rate ... although in more severe cases it can lead to retinal hemorrhaging and detachments resulting in blindness. Thyroid problems have ...
... night blindness. Vitamin A deficiency (VAD) caused night blindness is a reversible difficulty for the eyes to adjust to dim ... Reversible night blindness is an early indicator of low vitamin A status. Plasma retinol is used as a biomarker to confirm ... During diagnosis, night blindness and dry eyes are signs of vitamin A deficiency that can be recognized without requiring ... An early sign of vitamin A deficiency is night blindness. Vitamin A in the form of retinoic acid is essential to normal ...
Usually, the rod cells of the retina are affected first, leading to early night blindness (nyctalopia) and the gradual loss of ... The degeneration is usually first noticed as night blindness (nyctalopia); peripheral vision is gradually lost, restricting the ... it is helpful to diagnose children well before they develop the characteristic night blindness. Some preliminary studies have ... Foundation Fighting Blindness. ASIN B00071QLJ6. Vernon M (1969). Usher's syndrome: Deafness and progressive blindness : ...
Night blindness by three to five years old, blind one to two years later. Labrador Retriever - Night blindness by four to six ... Night blindness by six months old, blind by three to five years old. Rod dysplasia has now been bred out of this breed. ... Night blindness by six to eight weeks old, often blind by one year old. Sloughi - A DNA test can identify whether Sloughis have ... Poodle - Night blindness by three to five years old, blind by five to seven years old. English Cocker Spaniel - Occurs late in ...
Homozygous leopards are substantially more prone to congenital stationary night blindness. Congenital stationary night ... blindness is present at birth and is characterized by impaired vision in dark conditions. Lethal white syndrome is a genetic ...
"Vitamin A-rich porridge for Boarding Khalwa students with night blindness". Sudanese Journal of Paediatrics. 14 (1): 45-50. ... Mondays are dedicated to bringing firewood to light a fire at night, or "Al-Taqabah", and it is called the day of Al-Fazaa. On ... The school day is from three-thirty in the morning to ten in the evening. The day begins with a period called the "Daghishah," ... After evening prayer until ten, the student recites from memory seven parts, and it is called "the Seven," done in the old days ...
Oguchi disease is a form of congenital stationary night blindness (CSNB). Congenital stationary night blindness is caused by ... "Defects in the rhodopsin kinase gene in the Oguchi form of stationary night blindness". Nature Genetics. 15 (2): 175-8. doi: ... phospho-rhodopsin Mutations in rhodopsin kinase are associated with a form of night blindness called Oguchi disease. Rhodopsin ...
Congenital stationary night blindness (CSNB) is a rare non-progressive retinal disorder. People with CSNB often have difficulty ... The complete form of X-linked congenital stationary night blindness, also known as nyctalopia, is caused by mutations in the ... "Congenital Stationary Night Blindness (CSNB2) in Tennessee Walking Horses , Veterinary Genetics Laboratory". vgl.ucdavis.edu. ... The incomplete form of X-linked congenital stationary night blindness (CSNB2) is caused by mutations in the CACNA1F gene, which ...
Autosomal dominant congenital stationary night blindness is a disorder of the retina, which is the specialized tissue at the ... NIGHT BLINDNESS, CONGENITAL STATIONARY, AUTOSOMAL DOMINANT 2; CSNBAD2. *NIGHT BLINDNESS, CONGENITAL STATIONARY, AUTOSOMAL ... night blindness). For example, they are not able to identify road signs at night and some people cannot see stars in the night ... Mutations in the RHO, GNAT1, or PDE6B gene cause autosomal dominant congenital stationary night blindness. The proteins ...
... is when you cant see as well at night or in poor lighting. It is a symptom of an underlying disease, usually a retina problem ... Learn about the five causes of night blindness.. What are the most common causes of night blindness?. Night blindness has many ... What is night blindness?. Night blindness (nyctalopia) is your inability to see well at night or in poor light such as in a ... Night Blindness (Nyctalopia). Night Blindness (Nyctalopia) is a symptom of an underlying disease such as a retina problem. The ...
Medicinal plants preparations for night blindness The primary role of phytotherapy in the treatment of night blindness involves ... Herbal remedies for night blindness or nyctalopia Phytotherapy: ... Night blindness medicinal plants. Night blindness medicinal ... More information about night blindness diet.. VITAMINS FOR NIGHT BLINDNESS. Supplements of vitamin A for night blindness. ... Herbal remedies for night blindness or nyctalopia. Phytotherapy: Medicinal plants preparations for night blindness. The primary ...
Find all Natural Cures for Night Blindness only on NaturalCures.com - the worlds #1 resource of natural health cures and ... remedies, including Night Blindness . Become a member now! ... Night blindness, as its name implies, is a condition in which ... The primary symptom of night blindness is impaired vision during the night or in times of darkness. Objects become difficult to ... There are two primary causes of night blindness. In many cases, it is due to poor diet and nutritional deficiencies, especially ...
... night blindness or find a doctor at Mount Sinai Health System. ... Night blindness is poor vision at night or in dim light.. The ... Night blindness may cause problems with driving at night. People with night blindness often have trouble seeing stars on a ... The causes of night blindness fall into 2 categories: treatable and nontreatable. ... Contact your eye doctor if symptoms of night blindness persist or significantly affect your life. ...
Night blindness and decreased night vision is associated with retinal diseases such as dry age related macular degeneration, ... in the elderly with high blood cholesterol to prevent eye diseases such as AMD contributing to night vision and night blindness ... invention is for a safe and effective method of administering an opthalmological therapeutic agent for the treatment of night ... blindness and improving night vision, using insulin, and chlorin e6, preparations instilled into the conjunctival sac as ...
Find symptoms and other information about Night blindness-skeletal anomalies-dysmorphism syndrome. ... Night blindness-skeletal anomalies-dysmorphism syndrome. Other Names: Hunter-Thompson-Reed syndromeHunter-Thompson-Reed ... Night blindness-skeletal anomalies-dysmorphism syndrome is caused by harmful genetic changes, also known as pathogenic variants ... About Night blindness-skeletal anomalies-dysmorphism syndrome. Many rare diseases have limited information. Currently GARD aims ...
... or other Night Blindness causing conditions. Optometrist near you in Timonium, Maryland. Call 410-561-8050 ... The inability to see well at night can be the result of Myopia, Cataracts, Glaucoma, ...
WILLS EYE HOSPITAL AND PENN MEDICINE RETINA RESEARCH FIND IMPROVEMENT FOR NIGHT VISION IN ADULTS WITH CONGENITAL BLINDNESS. ... and Penn Medicines Scheie Eye Institute has led to improvements in night vision for patients with childhood-onset blindness. ... making it one of the most common congenital blindness conditions. The clinical study delivered gene therapy to the retina of ...
This page contains all of the Prevent Blindness Terms that start with N ... Night Blindness. Condition in which sight is good by day but deficient at night and in any faint light. ...
Adelaide Test ~ Pink Ball & Day Night Test : Wades Colour Blindness. Posted on the 24 November 2016 by Sampathkumar Sampath ... He however insists that he will cope with it in the day-night Test against SouthAfrica being played in Adelaide with the pink ... Australian wicketkeeper-batsman Matthew Wade, suffers from color blindness. ... crafty declaration on the first evening of the Adelaide Test, a call that left Steven Smith and Usman Khawaja fuming as David ...
Some causes of night blindness are treatable, while others are not, so the first step is a comprehensive eye exam to determine ...
AAMCO was proud to support Charity Vision in their goal to beat blindness which was highlighted in an epic fight night gala on ... AAMCO was proud to support Charity Vision in their goal to beat blindness which was highlighted in an epic fight night gala on ... AAMCO Helps Knock out Blindness by Sponsoring Inaugural Charity Vision Fight Night. ... For nearly 30 years, Charity Vision has been working to reverse the global epidemic of blindness.One hundred percent of ...
Theres no cure for blindness. But treatments can offer help for some people, depending on the cause and progression of their ... What Is Congenital Stationary Night Blindness?. Learn about congenital stationary night blindness (CSNB), an inherited eye ... 7 Common Causes of Blindness. We review seven of the most common causes of blindness in adults and children, and how to manage ... Can You Prevent Temporary Sun Blindness?. Powerful UV rays can damage your eyes and cause temporary blindness. Learn how to ...
Get a nutritional checkup Visit a knowledgeable professional to find out whether your night blindness is caused by a vitamin A ... Driving during the darker hours of the day can be difficult when you have night blindness. According to research or other ... Night Blindness (Holistic). About This Condition. Driving during the darker hours of the day can be difficult when you have ... Zinc helps night blindness in people who are zinc-deficient.. Dietary zinc deficiency is common, and a lack of zinc may reduce ...
Night Blindness. Is it hard to see at night, especially while driving? Is it tough to find your way around in dark places, such ... Nearsightedness, cataracts, keratoconus, and a lack of vitamin A all cause a type of night blindness that doctors can fix. ... That sounds like night blindness. Its a symptom, not a problem in its own right. ... Eyestrain can do it, and so can a late night, a lack of sleep, or allergies. If an injury is the cause, get it checked by your ...
Overview of noun night_blindness. The noun night blindness has 1 sense. *nyctalopia, night blindness, moon blindness -- ( ...
How Is Night Blindness Treated? A: Night vision glasses - or goggles - are different from night driving glasses. Their yellow ... Night blindness, also known as nyctalopia, is the inability to see clearly at night or in dim light (such as raining or dark ... BLUPOND Semi Polarized Night Driving Glasses, 4 Treatment for night blindness will vary depending on the cause. This keeps you ... Many people find it tiring to see clearly at night or in low light; some would even say they suffer from night blindness. Learn ...
Congenital Stationary Night Blindness: Blindness since birth. Can be due to inherited illnesses. ... Night Blindness as Complication of Obesity Surgery: This surgery can lead to impaired vision, as absorption of vitamin A may be ... Progressive Night Blindness: This can be caused by vitamin A deficiency, other diseases, or toxic effects of some drugs like ... Marked deficiency of vitamin A may lead to night blindness, and subsequently suitable amounts of vitamin A can help correct it ...
Night vision is often impaired but not totally lost.. CAUSES OF NIGHT BLINDNESS. Night blindness can be caused by various ... SYMPTOMS OF NIGHT BLINDNESS. The main symptom of night blindness is difficulty to see in the dark and also in dim light.. ... HOW TO PREVENT NIGHT BLINDNESS. Night blindness can be prevented by;. Eating foods rich in vitamin A such as; spinach, milk, ... Night blindness caused by shortsightedness can be corrected using corrective lenses. Cataracts can be removed surgically. Night ...
Night blindness does not necessarily mean that one cannot see at night, Rather NIGHT BLINDNESS is the inability of the eye to ... When the Rods stop responding to light, it leads to decreased night vision or night blindness. ... Difficulty walking around at night or dim lights.. *When it is dark out and the road illumination is poor, seeing is often a ... or ophthalmologist for a comprehensive eye examination is the best way to find out exactly what is causing your night blindness ...
Leopard - Congenital Stationary Night Blindness (CSNB). Contenu. *Léopard - Cécité nocturne congénitale non évolutive * ... 2013). Evidence for a Retroviral Insertion in TRPM1 as the Cause of Congenital Stationary Night Blindness and Leopard Complex ... 2011). An Insertion In TRPM1, The Genetic Cause Of Leopard Complex (LP) Spotting And Congenital Stationary Night Blindness ( ... 2012). Congenital stationary night blindness is associated with the leopard complex in the Miniature Horse. Veterinary ...
... or other Night Blindness causing conditions. Optometrist near you in Bristol, Connecticut. Call 860-512-7222 ... The inability to see well at night can be the result of Myopia, Cataracts, Glaucoma, ...
Chondroectodermal dysplasia with night blindness. Chondroectodermal dysplasia with night blindness is a rare genetic bone ... Chondroectodermal dysplasia with night blindness?. Our RARE Concierge Services Guides are available to assist you by providing ... Chondroectodermal dysplasia with night blindness. Get in touch with RARE Concierge.. Contact RARE Concierge ... hypodontia and night blindness. Osteopenia a tendency to present fractures talipes varus with abnormal gait ear infections and ...
... also known as night blindness makes it difficult for you to see at night as well as in areas that are dimly lit. ... Here is everything you need to know about night blindness:. Causes. Causes of night blindness can include:. • Nearsightedness. ... Nyctalopia, also known as night blindness makes it difficult for you to see at night as well as in areas that are dimly lit. ... The following foods are recommended if you wish to lessen your risk for night blindness:. • cantaloupes and mangoes. • sweet ...
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Learn how corrective lenses, surgery, and proper nutrition can help manage and alleviate night blindness symptoms. ... Explore night blindness, or nyctalopia, its signs, causes like cataracts, nearsightedness, retinitis pigmentosa, nutritional ... What is Night Blindness?. Night Blindness is a condition in which an individual finds it difficult to see objects at night or ... This becomes more severe at night and may cause Night Blindness.. Treatment of Night Blindness Caused Due to Nearsightedness: ...
  • The complete form of X-linked congenital stationary night blindness, also known as nyctalopia, is caused by mutations in the NYX gene (Nyctalopin on X-chromosome), which encodes a small leucine-rich repeat (LRR) family protein of unknown function. (wikipedia.org)
  • Night Blindness (Nyctalopia) is a symptom of an underlying disease such as a retina problem. (clevelandclinic.org)
  • Night blindness (nyctalopia) is your inability to see well at night or in poor light such as in a restaurant or movie theater. (clevelandclinic.org)
  • Night blindness (nyctalopia) occurs when a person has significant difficulty seeing in poorly lit environments. (jds.cz)
  • Nyctalopia, also known as night blindness makes it difficult for you to see at night as well as in areas that are dimly lit. (inneseyeclinic.com)
  • In medical terminology, Night Blindness is termed as Nyctalopia. (epainassist.com)
  • Night blindness , also called nyctalopia, occurs when a person struggles to see well at night or in dim lighting. (allaboutvision.com)
  • Only three rhodopsin mutations have been found associated with congenital stationary night blindness (CSNB). (wikipedia.org)
  • No systemic disease is associated with congenital stationary night blindness. (arizona.edu)
  • A number of other symptoms and problems can affect the eyes, including changes in the appearance of the eyes, color blindness, dry eyes, glare and halos, impaired depth perception, itchy eyes, light sensitivity, and night blindness. (msdmanuals.com)
  • People who have color blindness (dyschromatopsia) are unable to perceive certain colors, or they may perceive certain colors with different intensity than do people with normal color vision. (msdmanuals.com)
  • For instance, in the most common form of color blindness (red-green color blindness), people are less able to distinguish dark or pastel green or red or both. (msdmanuals.com)
  • Congenital stationary night blindness (CSNB) is a rare non-progressive retinal disorder. (wikipedia.org)
  • Congenital stationary night blindness (CSNB) can be inherited in an X-linked, autosomal dominant, or autosomal recessive pattern, depending on the genes involved. (wikipedia.org)
  • The X-linked varieties of congenital stationary night blindness (CSNB) can be differentiated from the autosomal forms by the presence of myopia, which is typically absent in the autosomal forms. (wikipedia.org)
  • Patients with CSNB often have impaired night vision, myopia, reduced visual acuity, strabismus and nystagmus. (wikipedia.org)
  • However, there is also a group of genetically heterogeneous disorders, with generally stable scotopic defects and without RPE changes, known as congenital stationary night blindness (CSNB). (arizona.edu)
  • A dim nighttime scene (left and right) looks much different (center) to an individual suffering from congenital stationary night blindness (CSNB). (thescitech.com)
  • A gene therapy to correct this condition has been shown to improve night vision in dogs and should be adaptable to humans with CSNB. (thescitech.com)
  • In 2015, researchers from the University of Pennsylvania's School of Veterinary Medicine learned that dogs could develop a form of inherited night blindness with strong similarities to a condition in people called congenital stationary night blindness (CSNB). (thescitech.com)
  • People with CSNB are unable to distinguish objects in dim-light conditions, which presents challenges when artificial lighting is unavailable or when driving at night. (thescitech.com)
  • The journal Proceedings of the National Academy of Sciences recently published the team's paper reporting its successful restoration of night vision to dogs born with CSNB. (thescitech.com)
  • The gene that the Penn Vet team corrected to fix the dogs' night vision impairment has also been implicated in certain cases of human CSNB, which opens the door to treating people with a similar gene therapy. (thescitech.com)
  • Treatment may be as simple as getting yourself a new eyeglass prescription or switching glaucoma medications, or it may require surgery if the night blindness is caused by cataracts. (clevelandclinic.org)
  • Nearsightedness , cataracts , keratoconus , and a lack of vitamin A all cause a type of night blindness that doctors can fix. (webmd.com)
  • Marked deficiency of vitamin A may lead to night blindness, and subsequently suitable amounts of vitamin A can help correct it too. (topdoctorsonline.com)
  • Contact your eye doctor if symptoms of night blindness persist or significantly affect your life. (mountsinai.org)
  • When Do Symptoms of Night blindness-skeletal anomalies-dysmorphism syndrome Begin? (nih.gov)
  • Night blindness may be an early sign of vitamin A deficiency. (kaiserpermanente.org)
  • Supplementing with beta-carotene, which the body converts into vitamin A, help correct such a deficiency and improve night blindness. (kaiserpermanente.org)
  • Which vitamin deficiency can cause night blindness? (wanderluce.com)
  • Which vitamin deficiency may cause evening blindness? (wanderluce.com)
  • Deficiency impairs immunity and hematopoiesis and causes rashes and typical ocular results (eg, xerophthalmia, evening blindness). (wanderluce.com)
  • Bitot spots are a sign of vitamin A deficiency (VAD), one of the major causes of preventable blindness in young children. (allaboutvision.com)
  • See your healthcare provider right away because night blindness can be a symptom of a serious disease. (clevelandclinic.org)
  • The primary symptom of night blindness is impaired vision during the night or in times of darkness. (naturalcures.com)
  • The main symptom of night blindness is difficulty to see in the dark and also in dim light. (healthgist.net)
  • Night blindness describes a symptom, not a disease. (cypresseyecentre.com)
  • The only thing that may termed as a symptom is that the individual will start finding it difficult to see objects clearly when the light is dim or during the evening hours. (epainassist.com)
  • If you have a family history of congenital blindness, or conditions that can lead to childhood blindness, your healthcare team may be able to provide screenings that can give you an idea of how likely you may be to pass these conditions on to your children. (healthline.com)
  • A first-of-its-kind gene therapy received approval from the Food and Drug Administration on Tuesday to treat a rare, inherited form of childhood blindness. (scientificamerican.com)
  • LCA is an eye disorder presenting at birth that primarily affects the retina and is found in roughly one in 40,000 newborns, making it one of the most common congenital blindness conditions. (willseye.org)
  • There are several types of congenital blindness and other diseases that are present at birth and result in immediate or early blindness. (healthline.com)
  • Good prenatal care can help prevent some forms of congenital blindness, but many are the result of genetically programmed disorders that can't be avoided. (healthline.com)
  • PHILADELPHIA, January 3, 2023 - A collaboration between Wills Eye Hospital and Penn Medicine's Scheie Eye Institute has led to improvements in night vision for patients with childhood-onset blindness. (willseye.org)
  • The procedure is called phacoemulsification where the cataract is removed and new lens is implanted for correct vision and thus get rid of Night Blindness. (epainassist.com)
  • People with this condition typically have difficulty seeing and distinguishing objects in low light (night blindness). (medlineplus.gov)
  • Symptoms include difficulty seeing when driving in the evening or at night, poor vision in reduced light, and feeling that the eyes take longer to "adjust" to seeing in the dark. (kaiserpermanente.org)
  • Difficulty while driving at night. (cypresseyecentre.com)
  • Difficulty walking around at night or dim lights. (cypresseyecentre.com)
  • If you are having eye problems such as difficulty seeing in the dark you should speak to your eye doctor to discuss the possibility you may have night blindness. (inneseyeclinic.com)
  • This can include difficulty transitioning from bright light to low light, difficulty driving at night or difficulty seeing in dimly lit rooms. (inneseyeclinic.com)
  • If you are experiencing difficulty seeing at night or in darker rooms set up an eye exam with your doctor. (inneseyeclinic.com)
  • People born with mutated RPE65 genes suffer from severe vision problems, including night blindness. (scientificamerican.com)
  • Night blindness does not necessarily mean that one cannot see at night, Rather NIGHT BLINDNESS is the inability of the eye to adapt to reduced illumination or dim light. (cypresseyecentre.com)
  • It is common for people who are myopic to have some difficulties with night vision, but this is not due to retinal disease, but rather optical issues. (clevelandclinic.org)
  • Night blindness is a feature of many pigmentary and other retinal disorders, most of which are progressive. (arizona.edu)
  • Spirulina supplements to people with vision problems, such as macular degeneration or night blindness could be very convenient. (botanical-online.com)
  • Sufficient quantities of vitamin A are needed for proper functioning of retina and to see properly during night time. (topdoctorsonline.com)
  • Eating a diet with adequate amounts of Vitamin A may help prevent night blindness. (topdoctorsonline.com)
  • You might must take vitamin B-12 individually from the above medication and dietary supplements - say, one within the morning and one at evening - so you may get the complete dose of vitamin B-12. (wanderluce.com)
  • 13 ]. The same authors reported that the easily prevented by sound nutrition, includ- maternal mortality rate among night- ing provision of vitamin A [ 3 ]. (who.int)
  • Chondroectodermal dysplasia with night blindness is a rare genetic bone development disorder characterized by proportionate short stature nail dysplasia (enlarged convex hypertrophic nails) hypodontia and night blindness. (globalgenes.org)
  • Scientists have successfully restored dim-light vision to dogs with an inherited disorder that causes night blindness. (thescitech.com)
  • Scientists have successfully restored dim-light vision to dogs with an inherited disorder that causes night blindness, a major step toward using the same gene therapy to help people with similar vision problems. (thescitech.com)
  • Gal A, Orth U, Baehr W, Schwinger E, Rosenberg T. Heterozygous missense mutation in the rod cGMP phosphodiesterase beta-subunit gene in autosomal dominant stationary night blindness. (medlineplus.gov)
  • Szabo V, Kreienkamp HJ, Rosenberg T, Gal A. p.Gln200Glu, a putative constitutively active mutant of rod alpha-transducin (GNAT1) in autosomal dominant congenital stationary night blindness. (medlineplus.gov)
  • CSNB1C, or type 1C, is one of four congenital nightblindness disorders with autosomal recessive inheritance. (arizona.edu)
  • Does using corrective lenses improve night vision? (mountsinai.org)
  • Your eye doctor can then prescribe corrective lenses to improve vision at night. (inneseyeclinic.com)
  • For example, they are not able to identify road signs at night and some people cannot see stars in the night sky. (medlineplus.gov)
  • Black currant ( Ribes nigrum ) Preparations with black currant fruit help capture more light, so that people with night blindness can see better at night or in low light. (botanical-online.com)
  • People with night blindness often have trouble seeing stars on a clear night or walking through a dark room, such as a movie theater. (mountsinai.org)
  • This article will review some of the most common causes of blindness that can be cured and what treatments could offer for people experiencing complete vision loss. (healthline.com)
  • People with night blindness (also called impaired dark adaptation) see poorly in the darkness but see normally when adequate amounts of light are present. (kaiserpermanente.org)
  • Zinc helps night blindness in people who are zinc-deficient. (kaiserpermanente.org)
  • In people and dogs with congenital stationary night blindness, the severity of disease is consistent and unchanged throughout their lives. (thescitech.com)
  • Some people experience glare (star bursts) or halos around bright lights, especially when driving at night. (msdmanuals.com)
  • Otherwise, people should take precautionary measures, such as minimizing driving at night or after receiving eye drops for an examination and avoiding looking directly at oncoming headlights while driving. (msdmanuals.com)
  • If you suspect you suffer from retinitis pigmentosa , seek medical attention immediately, because, if left untreated, it can lead to a progressive loss of sight and even complete blindness. (naturalcures.com)
  • Condition in which sight is good by day but deficient at night and in any faint light. (preventblindness.org)
  • Additionally, if you have prescription lenses in normal day glasses, it is important to ensure that you visit your optician or ophthalmologist to obtain prescription night vision glasses for driving - especially if you are really finding it difficult to deal with the glare from headlights or reflections that come from wearing glasses to correct your sight while driving. (jds.cz)
  • Night vision can be caused by a number of factors and a visit to your eye doctor will help discover what is affecting your sight so your doctor can find a solution. (inneseyeclinic.com)
  • Congenital stationary night blindness disorders are primarily rod dystrophies presenting early with symptoms of nightblindness and relative sparing of central vision. (arizona.edu)
  • protects eyes from vision disorders such as night blindness and eye ageing effects. (mygenericpharmacy.com)
  • More information about night blindness and its natural treatment . (botanical-online.com)
  • Once Night Blindness is confirmed then the physician will formulate a treatment plan to get rid of this condition. (epainassist.com)
  • No, there's no cure for blindness currently. (healthline.com)
  • Also, improving diet habits will help improving vision and cure Night Blindness to some extent. (epainassist.com)
  • Even though this may not be a permanent solution for nearsightedness but it will help get rid of Night Blindness as least to a certain extent. (epainassist.com)
  • Night blindness, as its name implies, is a condition in which vision becomes impaired during the night or in times of darkness, making it difficult, and in some cases, impossible to distinguish objects or read signs. (naturalcures.com)
  • Although the term "night blindness" implies total loss of vision, this is usually not the case. (healthgist.net)
  • Because the low-light sensing rods feed only into the ON pathway, individuals with CSNB1 typically have problems with night vision, while vision in well-lit conditions is spared. (wikipedia.org)
  • Night blindness is prevented or improved with a diet rich in plants that stimulate the absorption of light on the retina. (botanical-online.com)
  • Night blindness is poor vision at night or in dim light. (mountsinai.org)
  • The lenses within these yellow glasses for night driving are polarized so that reflections are kept to a minimum, while the yellow tint seeks to diminish blue light that comes from full beam headlights. (jds.cz)
  • They're an ideal option not just for driving at night, but also at dusk when the fading light tends to play tricks on many drivers, and on cloudy or snowy days when glare can be extra bad. (jds.cz)
  • The eyes need to adjust properly in order to see well at night or in low-light conditions. (cypresseyecentre.com)
  • When the Rods stop responding to light, it leads to decreased night vision or night blindness. (cypresseyecentre.com)
  • 2019 ( https://www.who.int/nutrition/publications/UNICEF-WHOlowbirthweight-estimates-2019/en/ ). (who.int)
  • As well, genetic conditions like retinitis pigmentosa cannot be treated and therefore you will have to avoid night driving. (inneseyeclinic.com)
  • Poor evening imaginative and prescient and white growths on the eyes. (wanderluce.com)
  • Blupond Night Driving Glasses - The Best Anti-Glare HD Night Vision Driving Glasses on the List Knight Visor, the manufacturer, says that these Blupond Night Driving Glasses are not exactly designed to improve your vision, at least not instantly. (jds.cz)
  • He shares with you that he has been advised by his family to use nopal (prickly pear cactus) and to add cinnamon and fenugreek to his food, which his mother is very happy to do for the evening meal because she also believes that these foods and spices will benefit his diabetes. (medscape.com)
  • In many cases of night blindness, these symptoms disappear during daylight. (naturalcures.com)
  • The overall quality of vision of an individual suffering Night Blindness is less and even in broad daylight the vision will be somewhat hazy. (epainassist.com)
  • Driving during the darker hours of the day can be difficult when you have night blindness. (kaiserpermanente.org)