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PubMed1990

Concurrent visual conversion reaction and simulated colour vision defects in a 12-year-old child.

Visual conversion reaction (VCR) is a psychosomatic anomaly which occasionally manifests in children, most commonly in the form of reduced vision and visual field defects. Malingering or conscious simulation for secondary gain would appear to be rare in children but occasionally VCR and simulation coexist. A case history is presented of a 12-year-old child with behavioural and reading difficulties who manifested reduced vision most probably attributable to VCR and severe colour deficiency, which was best explained in terms of simulation or malingering.

Child↗

PubMed1995

Impaired colour discrimination among workers exposed to styrene: relevance of a urinary metabolite.

OBJECTIVES: To survey the loss of colour vision among Japanese workers who have been exposed to styrene concentrations currently considered low (about 20 ppm). Also to assess the effects of styrene by examination of the nature of the relation between disorder of colour vision and age, alcohol consumption, and other variables. METHODS: Colour discrimination was examined in 64 male workers exposed to styrene (mean age; 38.0, mean exposed years; 7.0) and in 69 controls (mean age; 38.0). A standardised questionnaire was adopted to collect work history, occupational or non-occupational solvent exposure, alcohol consumption, and drug use. Colour vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the colour confusion index (CCI). RESULTS: The mean atmospheric styrene concentration was about 20 ppm. The mean urinary concentration of mandelic acid was 0.22 g/l. There was a significant difference in CCI between exposed workers and age matched controls. Colour vision of workers whose concentration of urinary mandelic acid was > or = 0.42 g/l was significantly impaired when compared with workers whose concentration was < 0.42 g/l. Multiple linear regression analysis that controlled confounding variables such as age, alcohol consumption, smoking, and educational attainment showed that the CCI was significantly related to the concentration of urinary mandelic acid. In both exposed workers and controls, the types of defects were mostly blue-yellow loss, although a few subjects showed complex loss. No one showed only red-green loss. CONCLUSIONS: These findings suggest that exposure to moderate styrene concentrations can lead to impairment of colour vision, and that there is a significant correlation with the urinary metabolite of styrene.

Adult↗

PubMed2005

Transmembrane S1 mutations in CNGA3 from achromatopsia 2 patients cause loss of function and impaired cellular trafficking of the cone CNG channel.

PURPOSE: Achromatopsia 2, an inherited retinal disorder resulting in attenuation or loss of cone function, is caused by mutations in the alpha subunit of the cone cyclic nucleotide-gated (CNG) channel gene CNGA3. Examination of mutations that cluster in the first transmembrane segment of the protein may provide insight into its role in CNG channel structure, function, biogenesis, and pathophysiology. METHODS: The human CNGA3 gene was tagged at the C terminus with green fluorescent protein. Four mutations, Y181C, N182Y, L186F, and C191Y, were expressed in human embryonic kidney cells. Protein expression was evaluated with immunoblot analysis and cellular localization was determined by immunocytochemistry. Channel function was evaluated by patch-clamp electrophysiology. RESULTS: All the mutations result in loss of channel function, as determined by the failure of cGMP to activate wild-type currents in excised patches. Full-length mutant proteins were synthesized but retained in the endoplasmic reticulum. Glycerol treatment did not rescue channel function nor did coexpression with CNGB3, a subunit of native hetero-tetrameric cone channels. A control mutant, C191S, exhibited cGMP current activation with significantly reduced cooperativity, suggesting that mutations in the first transmembrane domain alter in inter- or intrasubunit communication. CONCLUSIONS: The results implicate the first transmembrane segment in both maturation and function of CNG channels. The defects are not reversed with glycerol, a chemical chaperone that rescues channel function in some channelopathies. Molecular analysis of achromatopsia 2 mutations may be useful in evaluating potential therapeutic approaches for treatment of this channelopathy.

Amino Acid Sequence↗

PubMed1988

Defective colour vision can impede information acquisition from redundantly colour-coded video displays.

Earlier findings showed that redundant colour coding decreased response times and reduced errors in carrying out various tasks that required information acquisition from the video display of an electronic flight instrument system. The results of this experiment showed that observers with defective colour vision have slower response times and higher error rates than normal observers for some of the tasks and that their performance is similar to that of colour-normal observers for a monochrome display. However, they were not disadvantaged when blue was used to colour code the target feature. Protanopes were shown to be especially disadvantaged in responding to a red 'fail' message.

Adult↗

PubMed1996

A comparative study of Hardy-Rand-Rittler and Ishihara colour plates for the diagnosis of nonglaucomatous optic neuropathy.

OBJECTIVE: To determine the ability of the Hardy-Rand-Rittler (HRR) and Ishihara colour plates to detect acquired colour vision defects in patients with nonglaucomatous optic neuropathy (NGON). DESIGN: Prospective study. SETTING: Neuro-Ophthalmology Unit of the Wilmer Eye Institute, Baltimore. PATIENTS: A total of 178 consecutive patients (349 eyes) referred to the Neuro-Ophthalmology Unit and the General Eye Service of the Wilmer Eye Institute and examined by two of the authors were enrolled from July 1992 to June 1993. OUTCOME MEASURES: Results of testing with HRR and Ishihara plates. RESULTS: Among the 202 eyes that were found to have no ocular disease on neuro-ophthalmologic testing, the HRR plates gave a normal result in 168 (83.2%), compared with 196 (97.0%) with the Ishihara plates (p < 0.0001). The HRR plates detected an acquired colour vision deficit in 48 (87.3%) of the 55 eyes with NGON, compared with 38 (69.1%) for Ishihara plates (p = 0.001). The values for the eyes with NGON with a visual acuity of 20/25 or better were 76.5% (13/17) and 35.3% (6/17) respectively (p = 0.008) and with a visual acuity less than 20/25, 92.1% (35/38) and 84.2% (32/38) respectively. CONCLUSIONS: For patients with unilateral or bilateral NGON, HRR plates are more likely than Ishihara plates to detect a colour vision defect, particularly when the visual acuity is 20/25 or better. However, neither test is sensitive enough to be used as the sole criterion for the diagnosis of NGON. The results of comparison of colour perception of the two eyes may be more useful than absolute colour vision responses, particularly in patients with unilateral disease.

Adolescent↗

PubMed2002

[Acquired disorders of color vision].

This article is a general view of acquired disorders of color vision. The revision of the best known methods and of the etiopathogenic classification is not very important in ophthalmology but on the other hand, the detection of the blue defect advertise and associated ocular pathology. There is a major interest in serious diseases as multiple sclerosis, AIDS, diabetes melitus, when the first ocular sign can be a defect in the color vision.

Color Perception Tests↗

PubMed2003

[Influence of long term occupational exposure to solvents on colour vision].

BACKGROUND: The study was designed to determine the influence of chronic occupational exposition of organic solvent mixtures on colour vision of car painters. SUBJECTS AND METHODS: The 123 subjects (2 groups differing in organic solvents exposure and 1 control group) were examined using Ishihara-Panel, Lanthony Desaturated Panel D-15, Velhagen-Panel, and Tritan-Album. RESULTS: In the Velhagen-Panel 3% of the probands currently exposed to organic solvents, and 11% of formerly exposed probands developed a blue/yellow vision defect for the right eye. All control subjects perfectly finished this panel. In the Tritan-Album 3% of currently exposed subjects and 26% of formerly exposed painters expressed a blue/yellow vision defect for the right eye, but also 7% of controls showed anomalies. Similar results were found for both panels with the left eye. The CCI difference in the D-15 test was significant between all three groups. CONCLUSION: The impaired colour vision may also be an important indicator of neuro-ophthalmological effects after long-term occupational exposure to organic solvents.

Adult↗

PubMed1978

Clinical analysis of colour vision deficiencies with The City University test.

The City University colour vision test (CUCVT) was used for the examination of 158 subjects suffering from congenital colour vision defects (36 protanopes, 122 deutanopes) and its results were compared with that of an anomaloscope and of the panel D-15. 23% of the subjects classified as protanopes and 98% of the subjects classified as deuteranopes by means of the anomaloscope were also classified as such by means of the CUCVT, while 93% of the subjects classified as protanomalous and 90% of the subjects classified as deuteranomalous by means of the anomaloscope gave normal answers at the CUCVT. The results of the CUCVT were almost the same as with panel D-15 except protanopia. The colour spots of each plate of the CUCVT were plotted on a CIE chromaticity diagram and the results of this study are also reported.

Adolescent↗

PubMed1988

The influence of homonymous visual field disorders on colour sorting performance in the FM 100-hue test.

An influence of visual field disorders on sorting performance in the FM 100-hue test is reported. Patients with left-sided field disorders performed worse in the conventional testing direction, i.e. from left to right, compared with patients with right-sided defects. Reversing the direction of sorting led, however, to a similar impairment in patients with right-sided field defects. Observations in normals tested under different conditions of hue sorting support the view that the difference obtained cannot be accounted for by a hemisphere difference in colour processing but by the strategy adopted by subjects.

Adolescent↗

PubMed1976

A new screening method for detecting colour vision deficiencies.

Diagnostic colour vision examinations are generally administered with the anomaloscope. But this instrument requires a lot of time and experience for the tests as well as for the interpretation of the results. In practical use, it will be sufficient in most cases to know whether normal colour vision is present or not, and it is not necessary to use sophisticated devices. So it was considered desirable during the TCU conference on colour vision defects held in London in March 1973 [1] to have a testing method for practical use which is both accurate and time saving. At the time when this demand was brought up, a new colour vision test was being developed by Rodenstock [2]. It enables semi-skilled personnel to perform the test independently of ambient light condition in only 20-30 sec and to effect a classification of the type of colour vision at the same time [3].

Color Perception Tests↗

PubMed1985

Adverse consequences of altering the Farnsworth-Munsell 100-Hue test.

Modifications of the Farnsworth-Munsell 100-Hue test (e.g., selection of new fixed-reference caps from within the test) have been proposed, with little or no theoretical justification or experimental verification. Predictions based on theoretical considerations of the underlying nature of the test and verified by experimental measurements on subjects with known color defects demonstrate that (1) modification can destroy the very nature of the test; (2) modification can alter axis determination and therefore, potentially, the diagnosis; (3) the resulting test scores cannot be compared reliably to established norms; and (4) accurate predictions of test performance can be made from theoretical considerations.

Color Perception↗

PubMed1993

Longitudinal comparison of temporal-modulation perimetry with white-on-white and blue-on-yellow perimetry in ocular hypertension and early glaucoma.

We obtained data over 3 years on temporal-modulation perimetry (TMP), standard automated [white-on-white (W/W)] perimetry, and short-wavelength-sensitive [blue-on-yellow (B/Y)] perimetry in ocular hypertensive (OH) patients and patients with early glaucomatous visual-field loss (EG). Evidence of visual-field defects was obtained with the use of both B/Y perimetry and TMP in the majority of OH and EG eyes that demonstrated progression on W/W perimetry as well as in all stable EG eyes. Using the nerve-fiber-bundle pattern to compare testing procedures, we determined that these defects were generally as extensive or more extensive than the concurrent W/W abnormalities. In terms of location over the 3 years of testing, TMP and B/Y defects were reasonably consistent in the EG eyes, somewhat less consistent in the OH eyes demonstrating progression, and both inconsistent and infrequent in the stable OH eyes. The greatest degree of overlap occurred between the location of defects obtained by use of the higher TMP frequencies (8 and 16 Hz) and that of defects obtained by use of B/Y perimetry. Since these two methods are thought to isolate different visual mechanisms subserved by different visual pathways, these results suggest that early glaucomatous visual-field damage as revealed by TMP and B/Y perimetry may not be specific to a single visual pathway.

Color Perception Tests↗

PubMed1990

Comparison of the standard and Adams desaturated D-15 tests with congenital colour vision deficiencies.

The Adams desaturated D-15 was designed to be administered to patients with acquired colour vision defects by simply reducing the chroma of the Munsell colours by 2 for each cap in the test. In this study, the performance of the Adams desat D-15 in the assessment of congenital colour vision deficiencies is evaluated. The standard D-15 and Adams desat D-15 tests were administered to 75 congenital red-green colour deficient subjects who had been diagnosed on the basis of their performance on the Nagel anomaloscope Mark 1. The results were analysed in terms of the directions, extent and specificity of errors and compared with the diagnosis on the Nagel anomaloscope. Of the 13 colour-deficient subjects who made no errors on the standard D-15, 1 failed the Adams desat D-15 and 2 made single crossings. No colour-deficient subject who failed the standard D-15 made anything less than a simple inversion of adjacent caps on the Adams desat D-15. The Adams desat D-15 did not perform as well as the standard D-15 in identification of the type of defect in dichromats. On the basis of these data, it is predicted that about 5% of dichromats will be mis-classified by the Adams desat D-15 whilst under 0.1% will be mis-classified by the standard D-15. However, with the anomalous trichomats, more crossings were made on the Adams desat D-15, particularly by the milder anomals, and a diagnosis was possible in more cases. Where a diagnosis was possible, it was also correct more often with the Adams desat D-15.(ABSTRACT TRUNCATED AT 250 WORDS)

Color Vision Defects↗

PubMed1977

The Mackenzie Memorial Lecture, 1977. Of divers colours.

I shall discuss the nature of the sensation of colour and the reason for our colour vision, leading on to the existence of defects in that sense. I will consider the different kinds of such defects and the arguments for the use of particular tests in varying circumstances. I report the result of a recent survey of the value of a careers advisory service for "colour blind" school children seen between 1965 and 1977 (primarily red-green blind). This leads to examples of the value of these tests in genetics, and in the early diagnosis of disease or toxicity. I shall also describe the various modifications I have made to the 100-hue test, with its eventual automation both for computation and recording. Finally, the recommendations I make for future progress cover routine examination, both on starting primary education and on entering secondary education, analysis of the colour task at work, and the adoption of an enlightened system of colour coding.

Adolescent↗

PubMed1986

Monochromatic electroretinogram of deutan defect in the presence of intense red adaptation.

Monochromatic electroretinograms (ERGS) of deutans were recorded in the presence of intense red adaptation. The responses of some deutans were barely detectable or remarkably reduced, with the maximum response at the same wavelength (570-580 nm) as that under white adaptation. Those of other deutans showed a slight shift of the peak wavelength and the spectral pattern toward the shorter wavelength side although the amplitudes of the responses were much lower than those of normals under the same adaptation. These two types of change of spectral response patterns by intense red adaptation were investigated in relation to the anomaloscopic findings. The presence of the peak shift of the spectral pattern caused by red adaptation may depend on the degree of contribution of the green cone system to color vision in the deutan.

Adaptation, Physiological↗

PubMed2000

The luminance fall in anomaloscope examination: clinical examples.

PURPOSE: The evaluation of the anomaloscope slope quotient in patients with acquired colour vision deficiency. METHODS: Two patients with Stargardt's disease in combination with protanomaly and deuteranomaly, respectively, were selected and also 3 patients with a presumed dominant optic atrophy of the protan type. The anomaloscope examination was performed according to the Linksz procedure. The luminance fall was calculated as the slope quotient SQ:Y units luminance fall per X units width of the matching range. RESULTS: The SQ of the 2 Stargardt patients was steeper than the SQ of congenital colour vision defectives, especially at the red end of the anomaloscope green-red mixture scale, indicating pathologic scotopization superimposed on the congenital deficiency. In optic atrophy of the protan type the SQ was flatter than in congenital deficiency, indicating that this deficiency has nothing to do with congenital protan deficiency. CONCLUSION: Calculation of the slope quotient SQ is helpful for the diagnosis of acquired colour vision deficiency, especially when the subject also has a congenital colour vision deficiency or is supposed to have such a deficiency.

Adult↗

PubMed1979

Lanthony's new color test--part III. The neutral zone.

With the New Color Test (NCT) the neutral zone was studied in hereditary and acquired dyschromatopsias. Acquired type III blue-yellow defects with neutral zone occurred in heredo-atrophies of the optic nerve, in edematous maculopathies, in choroidal atrophy, in myopia, in glaucoma and in retinitis pigmentosa. With exclusion of the autosomal dominant inherited cases, the type III neutral zone in retinitis pigmentosa becomes complicated by a type I neutral zone when the visual acuity dropped to 0.2.

Choroid↗

PubMed2004

Colour blindness in everyday life and car driving.

PURPOSE: The aim of the present work was to ascertain, through the administration of a psychosocial questionnaire, the difficulties that subjects with defective colour vision experience in carrying out everyday tasks and work, including driving a car with a driver's licence held for no more than 3 years. METHODS: Subjects with defective colour vision (n = 151) and subjects with normal vision (n = 302) completed a psychosocial questionnaire regarding the difficulties associated with congenital colour vision deficiency in daily life, work and driving a car. Subjects were diagnosed as colour-blind using the Ishihara test. RESULTS: Statistically significant differences between the two samples were found for daily life activities. Subjects with defective colour vision preferred daytime driving. At night, subjects with defective colour vision had difficulty identifying reflectors on the road and the rear signal lights of cars ahead of them. CONCLUSION: Colour-blind Calabrian subjects admitted to experiencing colour-related difficulties with a wide range of occupational tasks and leisure pursuits. In particular, colour-blind Calabrian subjects preferred daytime driving, and fewer drove regularly, compared to orthochromatics, who were indifferent to night or daytime driving.

Activities of Daily Living↗