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PubMed2004

Functional photoreceptor loss revealed with adaptive optics: an alternate cause of color blindness.

There is enormous variation in the X-linked L/M (long/middle wavelength sensitive) gene array underlying "normal" color vision in humans. This variability has been shown to underlie individual variation in color matching behavior. Recently, red-green color blindness has also been shown to be associated with distinctly different genotypes. This has opened the possibility that there may be important phenotypic differences within classically defined groups of color blind individuals. Here, adaptive optics retinal imaging has revealed a mechanism for producing dichromatic color vision in which the expression of a mutant cone photopigment gene leads to the loss of the entire corresponding class of cone photoreceptor cells. Previously, the theory that common forms of inherited color blindness could be caused by the loss of photoreceptor cells had been discounted. We confirm that remarkably, this loss of one-third of the cones does not impair any aspect of vision other than color.

Adult↗
PubMed2004

[Congenital achromatopsia: electroretinogram in early diagnosis].

PURPOSE: Achromatopsia is a hereditary disease responsible for congenital low vision. Patients present with nystagmus, abnormal visual behavior or photophobia. Only the electroretinogram (ERG) can confirm the diagnosis in infants. PATIENTS AND METHODS: Thirty children referred for nystagmus or low vision were included in this retrospective study. A complete ophthalmological examination, an ERG and when possible a color vision test (Ishihara, Farnsworth 15 Hue test) was done. A Ganzfeld ERG was performed in accordance with ISCEV standards in patients more than 6 years of age. In younger patients, a simplified method using electroluminescent diode stimulation was used and a comparative ERG in accordance with ISCEV standards was performed when the patients were old enough. RESULTS: The ERG response was identical in children and adults. It confirmed the diagnosis of achromatopsia: the scotopic components obtained in dark adapted conditions were normal, (scotopic a-wave, b2 wave). The photopic components, recorded in light-adapted conditions, in order to inhibit the scotopic response (photopic wave, b1 wave), were not recordable. The color vision tests confirmed color blindness; however, in some patients color denomination was correct. CONCLUSION: The simplified ERG procedures performed in our series were reliable in detecting achromatopsia. However, it may not be sufficient to discriminate complete from incomplete achromatopsia.

Adolescent↗
PubMed1985

Standard Pseudoisochromatic Plates part 2.

The Standard Pseudoisochromatic Plates part 2 are able to detect acquired blue-yellow color vision defects as well as acquired and congenital red-green color vision defects. One test plate might be age dependent. The value of 3 test plates is not clear.

Adolescent↗
PubMed2003

Wavelength dependence of the optomotor response in zebrafish (Danio rerio).

The action spectrum of motion detection in zebrafish (Danio rerio) was measured using the optomotor response in the light adapted state. The function has a single maximum at 550-600 nm, and is similar to the spectral sensitivity function of the L-cone type in the mid and long wavelength range. At shorter wavelengths the values of three of the five fish tested are lower. As in goldfish [Vis. Res. 36 (1996) 4025], the result indicates a dominance of the L-cone type with an inhibitory influence of M- or S-cones. Experiments with a red/green striped cylinder showed that the optomotor response was at minimum whenever the L-cone type was not modulated by the moving pattern. This demonstrates that motion vision in zebrafish is "color blind", using mainly one of the four cone types probably involved in color vision.

Animals↗
PubMed1996

[Phylogenetic elements in Goethe's theory of colors].

Phylogenetic findings in the field of human color vision are compared with Goethe's theory of colors. Goethe's research into nature was often based on his view that whenever you find complex ("mannigfaltige') natural phenomena, there has always been a development from simple phenomena. In this connexion his interest focused on the identification of primordial phenomena ("Urphänomene') and not on the temporal aspects of development. This was also true for his studies of color. Based on erroneous interpretations of prismatic experiments, he put forward the theory that all colors developed from the two primordial colors yellow and blue, which were, according to Goethe, the two "first and simplest colors'. Although some of his assumptions were incorrect, his theory has many similarities with current phylogenetic findings, according to which our color vision is derived from an original perception of two colors, possibly yellow and blue. This similarity needs clarification on an interdisciplinary level as well as research to determine the degree to which Goethe's own physiological condition influenced his study of colors. The author suggests that a reappraisal of this, the largest section of Goethe's scientific work is now necessary.

Color↗
PubMed1991

[Dyschromatopsias and pictorial art].

The influence of color vision defects on pictorial art was studied using three methods. 1) From a theoretical standpoint, the possibilities of choice of the color-blind painter are determined by the nature of his color perception. Characteristic errors result from the fact that he has to choose between many hues which are different to a normal individual but which all look the same to him. 2) Evaluation of the clinical cases of painters with dyschromatopsias has shown evidence of the following: a) the color-blind painter makes mistakes according to the type of color defect; b) if the color-blind painter makes several copies of the same model, he makes different mistakes at each attempt; c) when several color-blind painters make copies of the same model, they also make different mistakes, even when they suffer from the same type of color vision defect. Preferences for some colored patterns were studied by means of a forced choice procedure and choices of color-blind individuals were often characteristic of their dyschromatopsia. Recent clinical case of acquired dyschromatopsia reported in the literature are discussed, as is a personal case of a painter suffering from tapeto-retinal degeneration. This was a severe dyschromatopsia with a neutral zone in purple (so-called scotpic axis, by Verriest's terminology). The painting of this artist tended to be monochromatic, mainly in green and green-blue colors. 3) Recent studies in art history have shown that only the romantic etcher Meryon was definitively color deficient. The more dubious cases of the Polish painter Grottger and of Eugène Carrière are discussed and conclusions are negative. Among acquired dyschromatopsias, there have been many recent papers devoted to cataract dyschromatopsias, concerning the cases of Rouault, Monet and Mary Cassatt. The hypothesis of a degree of chromatopsia or dyschromatopsia of toxic origin in the case of Van Gogh is also assessed. In conclusion, the problem of the relations between congenital or acquired dyschromatopsias and pictorial art seems very complex and great care is required when making deductions and advancing hypotheses.

Color Perception↗
PubMed1980

Children's perception of Munsell colors.

This study examined perception of Munsell notation color by seven third-graders and three college adults (both with normal color vision) and three children (from the same family) who were red-green color blind. The stimuli varied in terms of Munsell Hue (red, green, and purple), Munsell Value (brightness), and Munsell Chroma (saturation). Each S judged the dissimilarity of 325 color pairs (from 26 stimuli). The data were analyzed via individual difference multidimensional scaling that defined a common perceptual space for the group. The results indicated that the third-graders' color perception was like that of the adults. The color circle was reproduced, as were dimensions based on Munsell Value and Chroma. The color deficient children's data did not fit into that common space. Their perception was guided primarily by the brightness of the stimulus. In sum, the data indicated that, for the domain of Munsell colors, results obtained from adults concerning the dimensionality of the color space could be applied to young children (as long as they have normal color vision).

Adolescent↗
PubMed2003

The cone visual pigments of an Australian marsupial, the tammar wallaby (Macropus eugenii): sequence, spectral tuning, and evolution.

Studies on marsupial color vision have been limited to very few species. There is evidence from behavioral, electroretinographic (ERG), and microspectrophotometric (MSP) measurements for the existence of both dichromatic and trichromatic color vision. No studies have yet investigated the molecular mechanisms of spectral tuning in the visual pigments of marsupials. Our study is the first to determine the mRNA sequence, infer the amino acid sequence, and determine, by in vitro expression, the spectra of the cone opsins of a marsupial, the tammar wallaby (Macropus eugenii). This yielded some information on mechanisms and evolution of spectral tuning of these pigments. The tammar wallaby retina contains only short-wavelength sensitive (SWS) and middle-wavelength sensitive (MWS) pigment mRNAs. This predicts dichromatic color vision, which is consistent with conclusions from previous behavioral studies ( Hemmi 1999). We found that the wallaby has a SWS1 class pigment of 346 amino acids. Sequence comparison with eutherian SWS pigments predicts that this SWS1 pigment absorbs maximally (lambdamax) at 424 nm and, therefore, is a blue rather than a UV pigment. This (lambdamax) is close to that of the in vitro-expressed wallaby SWS pigment (lambdamax of 420 +/- 2 nm) and to that determined behaviorally (420 nm). The difference from the mouse UV pigment (lambdamax of 359 nm) is largely accounted for by the F86Y substitution, in agreement with in vitro results comparing a variety of other SWS pigments. This suggests that spectral tuning employing F86Y substitution most likely arose independently in the marsupials and ungulates as a result of convergent evolution. An apparently different mechanism of spectral tuning of the SWS1 pigments, involving five amino acid positions, evolved in primates. The wallaby MWS pigment has 363 amino acids. Species comparisons at positions critical to spectral tuning predict a lambdamax near 530 nm, which is close to that of the in vitro-expressed pigment (529 +/- 1 nm), but quite different from the value of 539 nm determined by microspectrophotometry. Introns interrupt the coding sequences of the wallaby, mouse, and human MWS pigment sequences at the same corresponding nucleotide positions. However, the length of introns varies widely among these species.

Amino Acid Sequence↗
PubMed1998

Increased acquired dyschromatopsia among solvent-exposed workers: an epidemiology study on 249 employees of an aluminum-foil printing factory.

OBJECTIVE: To analyze the effects on color vision of chronic exposure to mixtures of solvents including ethyl acetate, ethanol, and ketones among the workers of a large factory specializing in the manufacture of photoengraved aluminum packaging. METHODS: We analyzed a group of 129 subjects who had been exposed to solvents for more than 3 years (mean age 40 years, range 25 59 years) and a nonexposed group of 120 subjects (mean age 41 years, range 21-57 years). The two groups had a similar length of service (17 and 19 years on average, respectively). The exposed subjects consumed more tobacco and alcohol than the nonexposed workers. The study involved administration of the Lanthony D-15 desaturated test. The subjects were classified as having or not having dyschromatopsia on the basis of Lanthony's criteria and the chromatic confusion index (CCI) was calculated according to Bowman's method. After observation of the work stations and analysis of an occupational questionnaire the findings were used to construct a cumulative exposure index covering the whole of each subject's working life. Air samples were taken at each work station and in each production sector to determine current exposure. RESULTS: The average cumulative exposure index was 194 (median 174, range 27-513). The average hygienic effect index (according to ACGIH recommendations), regularly used for atmospheres containing mixtures of products, varied between 12% and 27% of the occupational limit values permitted under French legislation. As regards color vision, 23% of the exposed group had dyschromatopsia, as did 13% of the nonexposed group, with the odds ratio (OR) adjusted for age and consumption of tobacco and alcohol being 1.99 (1.02, 3.89). The analysis of the dose-response relationship according to the cumulative exposure index showed an OR of 1.59 for the lowly exposed group (index < 174) and an OR of 2.40 for the highly exposed group (index > 174) as compared with the nonexposed group. Subjects with complex color vision loss (n=23) had a significantly higher cumulative exposure index than those with blue-yellow loss (n=23; 232 versus 155; P=0.04). The CCI was on average higher in the exposed group, but the difference between the two groups was not significant. CONCLUSION: The results of this study are in favor of an increased risk for impairment of chromatic discrimination among workers exposed to mixtures of solvents including mainly ethyl acetate, ethanol, and ketones.

Adult↗
PubMed1985

Retinal toxicity after high-dose cisplatin therapy.

Because of increasing complaints of visual dysfunction, 13 patients with refractory or recently diagnosed ovarian carcinoma were evaluated for possible cisplatin-induced ophthalmologic toxicity. All patients had received high-dose cisplatin (200 mg/m2 in five divided daily doses) over two to four cycles. Eight patients (62%) developed symptoms of blurred vision and three (23%) also developed altered color perception. Retinal toxicity in the form of cone dysfunction was documented by electroretinography and color vision testing in 11 patients. Three patients were studied prospectively. Two patients who developed cone dysfunction had normal ophthalmologic exams before the initiation of chemotherapy or after one cycle of cisplatin, suggesting a causal relationship between cisplatin therapy and subsequent retinal abnormalities. Though visual acuity improved off therapy, color vision abnormalities persisted as long as 16 months beyond therapy.

Adult↗
PubMed1995

Visual evoked cortical potentials and psychophysical determination of color contrast thresholds along different chromatic axes.

Color vision can be assessed by examining the color contrast threshold along various color axes. We investigated the possibility of determining these thresholds objectively by means of visual evoked cortical potentials. A color-calibrated flicker-free (112-Hz) monitor and a 14-bit-per-gun board allowed visualization of colors with specified xyY CIE 1931 coordinates. Horizontal grating, 1 c/deg were sinusoidally alternated at 8 Hz for both visual evoked cortical potential recordings and psychophysical determinations. Two healthy emmetropic 35 year-old subjects performed color brightness matching along each color axis, before any recording and reduction in color contrast. For each color axis, extrapolation to zero voltage of the visual evoked cortical potential amplitude versus log color contrast response allowed determination of the color contrast threshold. The visual evoked cortical potential-derived threshold changed considerably with the color axis, with evident intersubject differences. These differences were similar to those observed in the psychophysically determined thresholds. Visual evoked cortical potential responses to suitable chromatic stimuli allow determination of color contrast thresholds that correspond well to those determined psychophysically. Hence, with the visual evoked cortical potential, accurate objective assessment of color vision is feasible and may be useful in both research and clinical settings.

Adult↗
PubMed1996

Visual outcome in bilateral nonarteritic anterior ischemic optic neuropathy.

BACKGROUND: Nonarteritic anterior ischemic optic neuropathy (NAION) is a common cause of visual loss in the older population. Bilateral NAION is a well-documented entity; however, no study to date has compared the visual outcome between affected eyes. METHODS: The authors retrospectively reviewed the charts of 99 patients with diagnoses of NAION over 3 1/2 years. In the 23 patients with bilateral involvement, 16 were included in the study for analysis of final visual outcome between affected eyes. Snellen acuity, Ishihara color plates, and Humphrey automated perimetry were evaluated as the parameters of visual function. Descriptive analysis of the outcome between affected eyes for each parameter is presented as a frequency distribution of pre-defined groups. Statistical significance is established using nonparametric tests. RESULTS: Bilateral NAION was found in 23% (23/99) of the patients studied. The authors identified a high percent agreement between eyes with regard to visual acuity (81% within 3 Snellen lines), color vision (69% within 3 plates), and Humphrey visual field (75% within 5 decibels of mean deviation). Additionally, there was a statistically significant correlation between affected eyes for all three visual parameters: visual acuity (P = 0.043), color vision (P = 0.001), and Humphrey visual field (P = 0.039). CONCLUSION: The authors found a high percent agreement and statistically significant correlation in final outcome between affected eyes of patients with bilateral NAION for visual acuity, color vision, and visual field loss. With a larger series, it may be possible to predict the visual outcome of the second affected eye based on the parameters of the first eye.

Adult↗
PubMed1992

Dichromacy and its effect on a young male.

Deuteranopia is a dichromatic color vision defect which may cause problems for an individual asked to perform color-oriented tasks. This can especially create problems for grade school children in classrooms whose instructional material depends heavily on color. This case report presents a child with a deuteranopic color vision defect who was mistakenly labeled learning disabled because of his inability to learn and perform color oriented tasks.

Child↗
PubMed2005

Quality-of-life improvements in cataract patients with bilateral blue light-filtering intraocular lenses: clinical trial.

PURPOSE: To compare change in patient-reported vision-related and health-related functioning and quality of life (HRQOL) following bilateral implantation with a new blue light-filtering intraocular lens (IOL) with the results of a similar IOL that does not filter blue light. SETTING: Six clinical sites in the United States. METHODS: Patients were from 6 clinical sites in the United States that performed a high volume of cataract surgeries. The HRQOL assessments occurred via telephone while patients were at home. Patients requiring bilateral cataract extraction were randomly assigned to 1 of the 2 IOL groups for the first eye. The second eye was later implanted with the same type of IOL. Patients and HRQOL data collectors were treatment-masked, but investigators could not be. Health-related functioning and quality of life was measured with the 39-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-39) and 12-item Short Form Health Survey (SF-12). Assessments were at baseline before implantation in the first eye and 30 to 60 days and 120 to 180 days after implantation of the lens in the second eye. RESULTS: Both IOL types improved most aspects of patients' HRQOL including color vision and driving. The largest gains occurred on the VFQ composite, general vision, near activities, distance activities, driving, mental health, peripheral vision, and role difficulties scales. Significant gains also occurred on color vision and other vision-specific scales as well as the SF-12 physical component summary score. There were no significant differences in HRQOL gains between the IOLs. CONCLUSION: The blue light-filtering IOL improved color vision, driving, and other aspects of HRQOL in a manner similar to that of a lens that does not filter blue light.

Aged↗
PubMed2006

Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in humans.

This study investigated whether 12 participants with color-vision deficiency had superior visual discrimination of color-camouflaged stimuli shown on a computer screen compared with 12 participants with normal trichromatic vision. Participants were asked to distinguish a circular pattern from other patterns in which textural elements differed from the background in orientation and thickness. In one condition, stimuli were single-colored, green or red; in the other condition, stimuli were color camouflaged with a green and red mosaic overlaid onto the pattern. Color-vision deficient participants selected the correct stimuli in the color-camouflaged condition as quickly as they did in the single-colored condition. However, normal color-vision participants took longer to select the correct choice in the color-camouflaged condition than in the single-colored condition. These results suggest that participants with color-vision deficiency may have a superior visual ability to discriminate the color-camouflaged stimuli.

Adult↗
PubMed2004

[Influence of Eqb 761 on the function of the retina in children and adolescent with long lasting diabetes mellitus--preliminary report].

PURPOSE: Early detection of patological function of the retina, before anatomical changes, plays very important role in monitoring of visual complications in patients with diabetes mellitus. The aim of the study was the evaluation of anatomical and functional changes in visual organ in children and adolescents with long lasting diabetes mellitus type 1 and taking Egb 761 (Tanakan Beaufour Ipsen) as an adjuvant. MATERIALS AND METHODS: Group consists of 15 patients, age between 11 and 19 years, with diabetes mellitus lasting 6-12 years. All patients had full ophthalmologic examination and color vision tests (Panel D 15 saturated and desaturated). The examination was done 3 times, every 3 months. Egb 761 was given: 1 tablet - 3 times a day, during 3 months. RESULTS: No diabetic retinopathy was found. The results of color vision test were better after therapy (25% of pathological results) and 3 months later (only 4 % of patients). CONCLUSIONS: 1. Egb 761 seems to be good adjuvant in patient with long lasting diabetes mellitus. 2. Color vision tests are sensitive tests of the retinal function and are easy to perform.

Adolescent↗
PubMedDate not supplied

Effect of sildenafil on ocular hemodynamics in 3 months regular use.

The aim of this study was to evaluate the effect of sildenafil on ocular hemodynamics in a group of men with erectile dysfunction in 3 months regular use. A total of 15 patients with erectile dysfunction were included in this prospective study. All patients received 50 mg doses of sildenafil (Viagra, Pfizer) two times per week regularly for 3 months. The following examinations were performed on both eyes before and after sildenafil treatment: best-corrected visual acuity (BCVA), intraocular pressure (IOP), color vision, anterior segment, and fundus examination. Using color Doppler imaging, we measured hemodynamic variables in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary artery (SPCA). No significant changes in BCVA, color vision and IOP were found after sildenafil treatment. The anterior segment and fundus examinations showed no abnormalities. All Doppler parameters of OA, CRA, and SPCA remained nonsignificant for both eyes after sildenafil treatment. Oral sildenafil in 3 months regular use seems to have no effect on ocular hemodynamics.

Adult↗
PubMed2003

Visual function in patients with optic nerve pallor (optic atrophy).

This cross-sectional study assessed the relationship between the degree of optic nerve pallor (optic atrophy) and visual function. Using a set of "gold standard" stereoscopic slides, the severity of optic atrophy for 270 eyes, each having sustained a bout of optic neuropathy, was graded. Good visual acuity was found in 55/86 (64.0%) mild, 54/119 (45.4%) moderate, and 21/65 (32.3%) marked optic atrophy eyes. Good visual field was found in 6/28 (21.4%) mild, 4/43 (9.3%) moderate, and 2/28 (7.1%) marked optic atrophy eyes. Good color vision was found in 31/46 (67.4%) mild, 12/62 (19.4%) moderate, and 7/31 (22.6%) marked optic atrophy eyes. A significant rank correlation was observed between optic atrophy and visual acuity (P < 0.001; rs = 0.356), visual field (P < 0.001; rs = -0.398), and color vision (P < 0.001; rs = -0.492). As the graded severity of optic atrophy increases, the proportion of eyes with good visual function decreases. Visual field, rather than visual acuity or color vision, appears to be a better indicator of the severity of visual loss, when optic atrophy is present.

Cross-Sectional Studies↗