Tests for partial sex-linkage in total color-blindness.
Explore the source record for details and available documents.
Blindness↗
SEARCH · Search PubMed
Results for “Color Vision”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[Heredity of daltonism; new observations of siblings of parents with different types of color blindness].
Explore the source record for details and available documents.
Color Perception↗
Linkage disequilibrium between glucose-6-phosphate dehydrogenase deficiency and congenital color blindness in Turkish population.
No erythrocyte glucose-6-phosphate dehydrogenase (G6PD)-deficient person was detected among 90 male patients with congenital color blindness (CCB) diagnosed at the Ophthalmology Clinic of our Hospital. Eighteen complete G6PD-deficient subjects had normal color vision. These results suggest that there is a linkage disequilibrium between CCB and G6PD genes.
Color Perception Tests↗
A survey of color discrimination in German ophthalmologists. Changes associated with the use of lasers and operating microscopes.
Color vision tests were performed on 211 German ophthalmologists during their annual meeting at Essen. The subjects also answered detailed questionnaires about their use of lasers and operating microscopes, and their ocular and general health. It was found that 33% of doctors who use lasers or operating microscopes have decreased color discrimination for colors in a tritan color-confusion axis (greater than 2 standard deviations above normal). There is a relationship between number of patients treated and the degree of threshold elevation. Thirty hours of using the operating microscope produces an increase in tritan threshold equivalent to one panretinal photocoagulation.
Adult↗
Chicken retinas contain a retinoid isomerase activity that catalyzes the direct conversion of all-trans-retinol to 11-cis-retinol.
Vertebrate retinas contain two types of light-detecting cells. Rods subserve vision in dim light, while cones provide color vision in bright light. Both contain light-sensitive proteins called opsins. The light-absorbing chromophore in most opsins is 11-cis-retinaldehyde, which is isomerized to all-trans-retinaldehyde by absorption of a photon. Restoration of light sensitivity requires chemical re-isomerization of retinaldehyde by an enzymatic pathway called the visual cycle in the retinal pigment epithelium. The isomerase in this pathway uses all-trans-retinyl esters synthesized by lecithin retinol acyl transferase (LRAT) as the substrate. Several lines of evidence suggest that cone opsins regenerate by a different mechanism. Here we demonstrate the existence of two catalytic activities in chicken retinas. The first is an isomerase activity that effects interconversion of all-trans-retinol and 11-cis-retinol. The second is an ester synthase that effects palmitoyl coenzyme A-dependent synthesis of all-trans- and 11-cis-retinyl esters. Kinetic analysis of these two activities suggests that they act in concert to drive the formation of 11-cis-retinoids in chicken retinas. These activities may be part of a new visual cycle for the regeneration of chromophores in cones.
Animals↗
The Glenn A. Fry Award Lecture 2003: Vision in elders--summary of findings of the SKI study.
PURPOSE: To assess a broad range of vision functions in a large older population, to investigate the impact of vision function loss on visual performance measures, and to determine whether low contrast vision measures can predict future loss of visual acuity. METHODS: A large battery of vision functions, including spatial vision measures, glare tests, visual fields, stereopsis, color vision, temporal sensitivity, reading performance, and face recognition, was administered to a population of 900 community-living older observers (mean age, 75.5 years; SD, 9.3 years; range, 58 to 102 years). A subsample (N = 596) was retested on average 4.4 years later (SD, 1.0 years). RESULTS: Each vision function is affected differentially by aging. Some functions show little change with age (e.g., standard clinically measured high contrast visual acuity), whereas others demonstrate drastic losses with increasing age. For the oldest age group (>90 years), vision function losses ranged from 1.2 times worse than young observers (critical flicker/fusion frequency) to 18 times worse than young observers (low contrast acuity in glare). Visual performance measures, such as reading or face recognition, are also significantly affected by aging even in those with intact visual acuity. The results demonstrate that low contrast vision functions can successfully predict subsequent loss of high contrast visual acuity. CONCLUSION: Nonstandard vision function measures show significant losses with age that cannot be predicted by standard clinical measures. Measures of low contrast vision function allow clinicians to identify and monitor those patients at high risk for future vision loss.
Aged↗
An estimate from pedigree data of the gene frequency for colour blindness.
Explore the source record for details and available documents.
Color Perception↗
Neuropsychological dysfunction, mood disturbance, and emotional status of munitions workers.
The objective of this study was to compare the neuropsychological function, emotional status, visual function, and illness prevalence of 265 former munitions plant workers (M age = 56.7 years, M years of education = 12.07; 201 African American, 64 White) exposed to organic solvents for an average of 17.03 years with that of a group of 77 unexposed controls (M age = 51.3 years, M years of education = 13.07; 30 African American, 47 White). Neuropsychological tests were selected from the World Health Organization Neurobehavioral Core Test Battery, Wechsler Adult Intelligence Scale-III (WAIS-III), and Wechsler Memory Scale-III (WMS-III) and also included the Brief Symptom Inventory, Profile of Mood States, Beck Anxiety Inventory, and Beck Depression Inventory. Vision tests included the Lanthony d-15 color vision, the Vistech Contrast Sensitivity, and the Snellen. The exposed group showed greater deficits than the controls in verbal learning (WMS-III Logical Memory I Learning Slope and Word Lists I Recall), visuomotor tracking speed (Cancellation H, WAIS-III Digit Symbol-Coding) and psychomotor function (Dynamometer and Grooved Pegboard), and dysfunction in emotional status, illness prevalence, and visual function. African American workers reported higher levels of exposure than Whites. Exposure relations demonstrated increased neuropsychological dysfunction with increased exposure.
Adult↗
A survey of molecular expression by photoreceptors after experimental retinal detachment.
PURPOSE: To describe changes in the localization patterns and levels of rod and cone photoreceptor proteins after experimental retinal detachment (RD). METHODS: Cat retinas were detached for 1, 3, 7, or 28 days, at which time the eyecups were placed in fixative for immunocytochemical analysis or homogenized for biochemistry. Immunocytochemistry was performed using 19 probes for molecules known to be associated with photoreceptors. Protein concentrations were determined using enzyme-linked immunosorbent assay or Western blot analysis. Cone cell death was analyzed by double labeling with TdT-dUTP terminal nick-end labeling and cone-specific antibodies. RESULTS: Although some cones died, many survived long-term RD. Although their profiles may have changed, rod photoreceptors continued to express most of the molecules studied as long as they were alive. In contrast, the cones failed to label with almost all probes specific to them after 3 to 7 days of detachment. The exception was phosducin, which localized to both rods and cones and, in 28-day detachments, increased to 180% of the amount in normal retina. CONCLUSIONS: Rods and cones respond differently to RD. This difference may account for a faster return of rod vision and for the lingering changes in color vision and acuity that are often reported after successful reattachment surgeries.
Animals↗
Development of photoreceptor mosaics in the primate retina.
The mosaic of rods and cones in the primate retina is the neuronal array where the visual world is first mapped onto the central nervous system. Rods, which mediate scotopic vision, and cones, which mediate photopic and color vision, are found in all vertebrate species. However, regional differences in the topographic arrangement and ratio of rods to cones vary dramatically among species, including different primates. Furthermore, the proportion and distribution of the wavelength-sensitive cone subtypes vary considerably between primates that occupy different visual habitats. What genetic or environmentally regulated mechanisms specify the position, phenotype, and ratios of photoreceptor subtypes? Available data suggest that the transient appearance of early-differentiating cones may serve to delineate basic species-specific retinal coordinates and determine the opsin phenotype of local assemblies of cones in the fetal photoreceptor mosaic. This article will summarize presently available data and our ideas of how the photoreceptor mosaic is organized in the adult primate retina, the features of these mosaics, which vary between primate species, and the developmental mechanisms, which may account for the emergence of photoreceptor position and specification of their phenotypes in the primate retina.
Animals↗
Phenotypic characterization of a large family with RP10 autosomal-dominant retinitis pigmentosa: an Asp226Asn mutation in the IMPDH1 gene.
PURPOSE: To evaluate the clinical features associated with the RP10 form of autosomal-dominant retinitis pigmentosa in 11 affected members of various ages from one family with a defined IMPDH1 mutation (Asp226Asn). DESIGN: Prospective, observational case series. METHODS: Visual function assessment included visual acuity, color vision, visual field, dark adaptometry, full-field electroretinography (ffERG), and multifocal electroretinography (mfERG). Ophthalmologic examinations, fundus photography, and optical coherence tomographic scans were also performed. Blood samples were obtained to screen for basic immune function. RESULTS: Visual acuity was slightly reduced in the teenage years and substantially reduced in association with cystoid macular edema (CME) at all ages. Color defects were observed in three patients (one teen, two adults). Dark-adapted thresholds were elevated. Visual fields were markedly constricted by age 40 (<or=20 degrees). Rod and cone a-wave and b-wave ffERG responses were small or nondetectable by age 20, with greater rod than cone loss at all ages. The normal to significantly delayed ffERG cone b-wave implicit times in different patients were explained by their mfERG implicit times from the central retina. The amplification factors (log S) and recovery kinetics derived from the full-field rod a-waves were normal. Optical coherence tomography revealed subretinal fluid accumulation in the majority of eyes. Cystoid macular edema was diagnosed in four patients. No unusual immunologic findings were noted. CONCLUSIONS: The Asp226Asn mutation is associated with a severe, early-onset form of retinal degeneration in members of this family.
Adolescent↗
PHOTOPIC FLICKER ERG IN CASES OF CONGENITAL NIGHT BLINDNESS AND TOTAL COLOR BLINDNESS.
Explore the source record for details and available documents.
Adaptation, Ocular↗
Autosomal recessive vitreoretinopathy and encephaloceles.
We conducted a ten-year follow-up of an unusual pedigree with an autosomal recessive vitreoretinal degeneration, severe myopia, and congenital encephalocele. All five affected members (four girls and one boy) also had early, recurrent bilateral detachments. Color vision testing disclosed an acquired tritan dyschromatopsia and electroretinography showed subnormal photopic and scotopic amplitudes, delayed b-wave implicit times and 30-Hz flicker-phase relations, and absent scotopic b-wave oscillations.
Child↗
Pupillary constriction to darkness in a patient with blue-cone monochromatism.
A 17 year old male patient presented with bilateral photophobia, poor color vision, visual acuity 20/80-20/200, nystagmus, and showed normal fundi. Electroretinography revealed evidence of blue-cone monochromatism. This patient showed constriction of the pupils to darkness or the paradoxic pupillary phenomenon.
Adolescent↗
Human tritanopia associated with two amino acid substitutions in the blue-sensitive opsin.
Tritanopia is an autosomal dominant genetic disorder of human vision characterize by a selective deficiency of blue spectral sensitivity. The defect is manifested within the retina and could be caused by a deficiency in function or numbers (or both) of blue-sensitive cone photoreceptors. We have used PCR, denaturing gradient gel electrophoresis, and DNA sequencing of amplified exons to detect in four of nine unrelated tritanopic subjects two different point mutations in the gene encoding the blue-sensitive opsin, each leading to an amino acid substitution. Segregation analysis within pedigrees and hybridization of oligonucleotides specific for each allele to DNA samples from control subjects support the hypothesis that these mutations cause tritanopia. These results complete the genetic evidence for the trichromatic theory of human color vision.
Arginine↗
Analysis of familial factors in bipolar affective illness.
Familial transmission of affective illness was studied using a family interview and family history method in a group of 35 bipolar manic-depressive patients. Morbidity risk for bipolar and unipolar affective illness in first-degree relatives is approximately 30% in this population. Probands with a positive family history for bipolar illness have a significantly greater risk for alcoholism in first-degree relatives. Four cases of father-to-son transmission are reported. Linkage of color vision deficiency or Xga blood group and affective illness within families could not be substantiated in our sample. We discuss evidence regarding the mode of transmission of affective illness.
Adult↗
[J.J. a daltonic painter].
Mr. J.J., painter, has been a professional artist for thirty years. On clinical examination of the color vision by pseudo-isochromatic plates, City University Colour Vision Test, standard and desaturated Panel-D 15, Farnsworth 100-hue test and Nagel's anomaloscop evidenced a typical hereditary deuteranopia. Neverless, the recognition and the denomination of coloured samples, presented singly or in simultaneous chromatic contrast, evidenced only a few errors. In an interview, the subject explained his difficulties with colours, mainly with green, and the procedures used to avoid mistakes in painting: knowledge of the names of colors written on tubes; precise order of arranging the tubes; use of a palette restricted to some basic hues, avoiding green. The subject artistic technique is based on drawing, on better perceived colours (i.e. the blues) and on value contrasts. He also enumerated his difficulties with colours in casual situations: clothes, traffic, food. Some reproductions of the works of the painter illustrate this study.
Color Vision Defects↗
Swelling and loss of photoreceptors in chronic human and experimental glaucomas.
OBJECTIVE: To determine whether outer retinal changes occur in chronic, presumed primary open-angle glaucoma (POAG). METHODS: The outer retinas from 128 human eyes with a diagnosis of chronic glaucoma (presumably POAG in most cases) and 90 control eyes were examined histologically by 3 masked observers for photoreceptor swelling and loss. Retinas from 9 rhesus monkeys with glaucoma induced experimentally by laser trabecular destruction were compared with 7 fellow (control) eyes. The mean pressure elevations in the eyes with laser trabecular destruction ranged from 26.6 to 53.6 mm Hg with durations varying from 7 to 33 weeks. RESULTS: Swelling of the red- and green-sensitive cones was observed in a statistically significantly greater proportion of human eyes with presumed POAG compared with the control eyes. Patchy loss of red/green cones and rods was also found in some of the glaucomatous retinas. In a subset of the human eyes with end-stage disease, cone swelling was a variable finding. Although no photoreceptor loss was found in the 9 monkey eyes with experimental glaucoma, 8 had swelling of their red/green cones that was remarkably similar to that seen in the human eyes. Swelling was not present in any of the control monkey eyes. CONCLUSIONS: The photoreceptors are affected by chronically elevated intraocular pressure. CLINICAL RELEVANCE: These findings may explain some of the abnormalities of color vision and the electrophysiological effects that have been observed in patients with POAG.
Aged↗