Blue-yellow Deficiencies Research Articles

Blue-yellow deficiencies in young moderate smokers

PurposeTo evaluate whether tobacco affects color vision in young moderate smokers. MethodsChromatic mechanisms of 13 moderate smokers (10–20 cigarettes/day and at least 5 years smoking) and 17 non-smokers in the 18–35 age range were assessed with the Farnsworth-Munsell 100-hue (FM100h) test and short wavelength automated perimetry (SWAP). ResultsFM100h Total Error Scores (TES) were higher for smokers, and although differences were not significant (p = 0.14), a linear model with principal component analysis was able to explain 95% of the variance in TES and red-green partial error scores, though not in blue-yellow partial error scores (p = 0.07), using the number of years as smokers and the number of cigarettes/day as predictors. SWAP sensitivity values were globally worse (p = 0.002) for smokers (25.7 + 6.2 dB) than for non-smokers (26.7 + 6.2 dB). In the upper visual hemifield sensitivity, total deviation and pattern deviation values were worse for smokers (p < 0.001). Differences in mean defect and pattern standard deviation were not significant (p > 0.05 in both cases). The number of out-of-limits points in the total difference and pattern difference map were significantly larger for smokers. After correcting for multiple comparisons, only the differences in the upper visual hemifield were significant. ConclusionsThis pilot study suggests that even young moderate smokers show small sensitivity loss in the blue-yellow mechanism, it is statistically significant, restricted to the upper visual hemifield. This corresponds to a retinal region where literature reports a lower density of retinal ganglion cells and where, therefore, the chromatic mechanisms would be more fragile.

Impairment of acquired color vision in multiple sclerosis: an early diagnostic sign linked to the greatness of disease.

To assess the type and degree of both red-green and blue-yellow color vision deficiencies of Calabrian males affected by multiple sclerosis. Eighty Calabrian male patients were enrolled (age range 18-70years; mean age 40.6±12.4years) showing a disease duration mean of 10.6±8.2years (range=0.5-46years) coming from the Institute of Neurology, Magna Graecia University, Catanzaro. Optic neuritis present in the medical histories of the 21 patients does not influence color vision. Excluding seven colorblind subjects and one affected by a bilateral maculopathy, the analyzed sample group was 72. Seventy controls were matched for age and sex. An ophthalmologist examined all patients and controls in order to rule out diabetic retinopathy, cataracts, senile maculopathy, or ocular fundus' anomalies. The Ishihara test identified the colorblind patients. The City University Test screened for people with abnormal color vision by grading the severity of color vision deficiency. The second part of the City University Test as well as the Farnsworth Test confirmed both the color vision deficiency type and degree. Fifty-one percentage (37/72) of the patients showing a color vision deficiency were subdivided into two subgroups: subgroup one showed red-green deficiency (57%, 21/37); subgroup two showed a coupled red-green and blue-yellow deficiency (43%, 16/37). Furthermore, we found two distinct curves showing a groove within the first 10years of the disease. Both monocular and binocular analyses allowed us to identify the patients showing the monocular color vision deficiency, but they were well compensated by binocular vision. We think that the majority of the patients with the red-green deficiency will develop the coupled red-green and blue-yellow deficiency in the latter years of multiple sclerosis.

Blue-yellow deficiency in workers exposed to low concentrations of organic solvents.

To evaluate the effects of low concentrations of organic solvents on color vision. Color vision was examined in 24 workers exposed to mixtures of solvents and in 24 control subjects. Exposure to mixtures was below the threshold-limit values. Color vision ability was assessed using the Ishihara plates (to screen for congenital dyschromatopsia), the Farnsworth panel D-15 test, the Lanthony desaturated panel D-15 test, and the Standard Pseudoisochromatic Plates part 2 (SPP2 test). The comparatively less sensitive Farnsworth panel D-15 test failed to show any difference between the groups, but the Lanthony panel D-15 desaturated test as well as the SPP2 test showed a significant impairment in the exposed group. Errors were of the blue-yellow type. This study gives further evidence that even mixtures of organic solvents at concentrations below the threshold-limit values may impair color vision.

Appearance of color for small, brief, spectral stimuli, in the central fovaea.

While color-vision characteristics of tritanopia (blue–yellow deficiency) are well known to occur with small fields in the central fovea, the possibility of similar confusions as a function of brief duration has previously only been suggested. The problem has been investigated in this study by determining the color names given by nine color-normal and two deuteranopic observers to spectral stimuli from 565 to 590 mμ and to a white light. The test stimuli, all presented foveally, subtended diameters of 54, 21, and 11 min at durations of 200 and 20 msec. For stimuli presented at small subtense and short duration, green was sometimes seen as blue or blue–green, a neutral band was found in the yellow–green (570–580 mμ), and no confusion was found between reds and greens. The degree of tritanopic-like color confusions in the fovea is related to both the exposure time and the size of the test area. The results are discussed in relation to the foveal vs small-field characteristics of apparent tritanopia.