The natural killer activity and indices of the interferon status of patients with recurrent genital herpes being treated with ridostin

There are many advantages to the computerization of colour vision tests. However, previous computerized colour vision tests have involved equipment and methods not commonly used in clinical practice. We created computer emulations of the City University Colour Vision Test (CUT), Ishihara plates and American Optical Hardy-Rand-Rittler (AO-HRR) plates using a commonly available 24-bit colour Macintosh computer. Our colour monitor was calibrated to standard display white (D65), and colour plates were imaged with a colour scanner. The computerized colour images were compared with the standard test plates in a sample of 21 subjects with normal colour vision, 10 patients with congenital red-green defect and 1 patient with an acquired mixed colour defect. The computer images of the three tests correlated well with their conventional counterparts on kappa statistic analysis (p < 0.001), for both the colour normal and colour defective groups. We conclude that our computer emulations of the CUT, Ishihara and AO-HRR tests screen subjects with normal colour vision with high specificity and delineate congenital colour defects with a sensitivity comparable to that of their conventional counterparts.     

Colour vision in AIDS patients without HIV retinopathy

Patients suffering from AIDS develop ocular complications, the most frequent being HIV retinopathy. It is however not clear, if functional visual impairments can be observed as early indicators of ocular complications, before clinical diagnosis of HIV retinopathy is made at fundus examination. To address this issue, we measured colour vision in a group of 49 AIDS subjects with normal clinical fundi using the 'two equation method'. This method, combining red-green Rayleigh and the blue-green Moreland metameric matches, enables more complete and quantitative assessments of colour vision than those based on pigmentary tests. Data were collected on our computer controlled colorimeter and compared to those of normal subjects. While most AIDS subjects without HIV retinopathy demonstrated normal colour vision, a significant portion of them had wider matches than normal subjects (11% for the Rayleigh equation and 16% for the Moreland equation). Furthermore, matching ranges of the Moreland equation were significantly correlated with CD4 lymphocyte counts. Patients with low CD4 values tended to produce larger matching ranges than the patients with high CD4 values. A within subject study on 17 patients confirmed this trend and showed that the patients who increased/decreased their CD4 blood counts generally improved/impaired their colour discrimination in the Moreland match. No such correlation was found between the matching ranges of the Rayleigh equation and the CD4 counts. These results show that colour discrimination is slightly reduced in some AIDS subjects, although there are no detectable ocular complications. They also suggest two different types of colour vision impairments in AIDS patients without retinopathy: one reversible process affecting colour discrimination in the blue-green range; and another irreversible process affecting colour discrimination in the red-green range.     

Further data on biometric correlations of central corneal thickness

Central corneal thickness measured in 126 young men aged from 18-21 years was correlated to a number of ocular and other parameters. The frequency distribution was skewed towards the lower end, but the deviation could not be statistically supported. No correlation between corneal thickness and birth weight was found. Other characteristics not correlated in this material to corneal thickness were corneal astigmatism, refraction, visual acuity, optic disc and retinal abnormalities, red-green colour vision defects, ABO and rhesus blood-groups, EEG abnormalities, chromosomal abnormalities, hearing defects, ear abnormalities and quality of the hair. The findings in this study, although mainly of negative character, stress the relative independence of the central corneal thickness as a biometric parameter.     

Effect of vitamin B6 on the side effects of a low-dose combined oral contraceptive

PURPOSE: To evaluate acquired color vision defects in glaucoma patients and glaucoma suspects. MATERIAL AND METHODS: 52 subjects (102 eyes) divided into four groups (with primary open angle glaucoma, normal tension glaucoma, ocular hypertension and with glaucoma-like optic disc) were examined with the IF-2 All-Color Anomaloscope. In all cases both the red-green equation of Rayleigh and the blue-green equation of Moreland were tested and three variables were determined: setting (matching) range (SR), calculated mid point (matching mid point) (CMP) and anomalous quotient (AQ) as compared to control group. RESULTS: No significant changes were found in the variables of the Rayleigh equation. However, in the blue-green equation SR was significantly enlarged in all tested groups and CMP was significantly shifted towards the short wavelength end of the match in first three groups. These results indicate a diminution of the color discriminating sensitivity in the short wavelength half of the visible spectrum and diminution of the blue cone sensitivity in glaucoma patients as well as in ocular hypertension (p < 0.001). In patients with glaucoma-like optic disc the setting range was enlarged in less degree (p < 0.01) without changes in the remaining variables (p > 0.05) what may be indicative of early stage of disease before the perimetric changes. CONCLUSION: Blue-green colour vision testing with the anomaloscope may serve as an additional test in the diagnostics of glaucoma. Glaucoma suspects with blue colour vision disturbances require the most careful investigation and if need be the recommendation of early treatment.     

Acquired colour deficiency in patients with Parkinson's disease

The blue cone pathway is reported to be affected early in Parkinson's disease (PD) and acquired type three (tritan) defects may occur. Sixty-one patients attending a treatment and rehabilitation centre for PD were examined with clinical colour vision tests. Seven of 13 patients, for whom the diagnosis of PD was equivocal or who had other medical conditions, were identified as having tritan colour deficiency. Results for the remaining 44 PD patients were compared with 40 age matched controls. Ten PD patients (22.7%) had tritan defects. Tritan defects were not found in the control group but performance on some tests was age related. We conclude that clinical tests for tritan colour deficiency are unlikely to be helpful in identifying PD.     

Vision screening in junior schools

A prospective study of routine school vision tests in 1809 children aged 8 and 10 y was undertaken in schools in the Cambridge Health District over two years (1988-1990) to establish whether a significant number of defects of vision were detected. Although the visual acuity of 31% of children who had an abnormal test was recorded as abnormal, most abnormalities were minimal. Only 15 (0.83%) had newly diagnosed problems requiring treatment. Almost all children with marked visual abnormalities had already been detected before school entry, at the 5 y school vision test or on another occasion. Near vision testing did not identify any previously undiagnosed child with significant defects who did not also have distant vision abnormalities. Satisfactory colour vision test results had been recorded for most children at the 5 y school entry vision test. These data do not justify the continued use of routine screening in junior schools.     

Analysis of glutaminase activity and RNA expression in preimplantation mouse embryos

The efficiency of the American Optical Company (Hardy, Rand and Rittler) (HRR) plates for screening, grading and classifying red-green colour deficiency was examined for 401 male colour deficient subjects previously identified and diagnosed with Nagel anomaloscope. There were 83 protanopes, 30 protanomalous trichromats, 96 deuteranopes and 192 deuteranomalous trichromats. Screening sensitivity was found to be 100% for dichromats and 96.4% for anomalous trichromats based on one screening error (35 subjects, including 7 dichromats, where identified by a single error). Thirty subjects (13.5%) made errors on screening plates only and were identified as having minimal colour deficiency. The HRR grading system did not distinguish dichromats and anomalous trichromats; 54% of dichromats were graded as having moderate rather than severe colour deficiency. Protan/deutan classification was correct for 95% of subjects who failed grading plates. HRR grades for anomalous trichromats were compared with the anomaloscope matching range and with pass or fail of the D15 test. The results show that only two rather than four grading categories can be distinguished by the HRR plates and that both the D15 and the HRR plates are needed in a vocational test battery to establish the severity of colour deficiency.     

Scholarly mission. Fostering scholarship in research, theory, and practice

PURPOSE: Color vision testing in young children typically is precluded by the motor and cognitive skills required by standard tests; yet this information can be useful for diagnosis and counseling in many conditions. The purpose of this study is to evaluate a visual evoked potential (VEP) method for assessing red-green color vision anomalies in pediatric patients. METHOD: The relative chromatic luminance (C = R/R + G) of a rapidly reversing red-green checkerboard was varied across a wide range within a short viewing period (10 sec). Swept-parameter VEP methods were used to measure the cortical response to the range of C presented. RESULTS: Individuals with normal color vision exhibit a VEP response that exceeds noise levels across all values of C, often with an amplitude minima near the photopic equiluminant point (C = 0.5). Results from children with established protan and deutan color vision anomalies show loss of VEP amplitude and phase at values of C consistent with the respective color defect. A patient with achromatopsia showed a generalized depression of VEP response across all values of C tested. CONCLUSION: Color sweep VEP techniques appear promising for the clinical assessment of color status in pediatric patients.     

Stereoacuity and colour contrast

We have measured the contrast dependence of stereoacuity using both horizontally and vertically oriented, isoluminant (red-green) and isochromatic (yellow-black), 0.5 c/deg Gabor patches. For comparison, contrasts were computed in multiples of detection threshold, where detection threshold was defined as the contrast required for the stimulus to be simultaneously detectable in each eye. Disparity thresholds (1/stereoacuity) for vertical chromatic Gabors were higher than those for vertical luminance Gabors by a factor of between 4 and 9 depending on contrast, and declined less steeply with contrast. Disparity thresholds for horizontal chromatic Gabors were very high (130-210 min arc) compared with horizontal luminance Gabors (by a factor of between 9 and 17) and were only measurable at contrasts above 10 times simultaneous monocular detection threshold. These results support the view that chromatic stereoscopic processing is less precise than luminance stereoscopic processing, and that there is a special deficit in the processing of disparity with horizontally oriented chromatic stimuli. The implications of these results for the role of colour vision in stereopsis are discussed.     

Motion coherence across different chromatic axes

It has been reported that equiluminant plaid patterns constructed from component gratings modulated along different axes of a cardinal colour space fail to create a coherent impression of two-dimensional motion [Krauskopf and Farell (1990). Nature, 348, 328-331]. In this paper we assess whether this lack of interaction between cardinal axes is a general finding or is instead dependent upon specific stimulus parameters. Type I and Type II plaids were made from sinusoidal components (1 cpd) each modulated along axes in a cardinal colour space and presented at equivalent perceived contrasts. The spatial angular difference between the two components was varied from 5 to 90 deg whilst keeping the Intersection of Constraints (I.O.C.) solution of the pattern constant. Observers were required to indicate the perceived direction of motion of the pattern in a single interval direction-identification task. We find that: (i) When plaids were made from components modulated along the same cardinal axis, coherent "pattern" motion was perceived at all angular differences. As the angular difference between the components decreased in a Type II plaid, the perceived direction of motion moved closer to the I.O.C. solution and away from that predicted by the vector sum. (ii) A plaid made from components modulated along red-green and blue-yellow cardinal axes (cross-cardinal axis) did not cohere at high angular differences (> 30 deg) but had a perceived direction of the fastest moving component. At lower angular differences, however, pattern motion was detected and approached the I.O.C. solution in much the same way as a same-cardinal axis Type II plaid. (iii) A plaid made from a luminance grating and a cardinal chromatic grating (red-green or blue-yellow) failed to cohere under all conditions, demonstrating that there is no interaction between luminance and chromatic cardinal axes. These results indicate that there are conditions under which red-green and blue-yellow cardinal components interact for the purposes of motion detection.     

Morphology of P and M retinal ganglion cells of the bush baby

P/midget ganglion cells mediate red-green color opponency in anthropoids. It has been proposed that these cells evolved as a specialization to subserve color vision in primates. If that is correct, they must have evolved about the same time as the long-wavelength ('red') and medium-wavelength ('green') pigment genes diverged, thirty million years ago. Strepsirhines are another group of primates that diverged from the ancestor of the anthropoids at least 55 million years ago. If P/midget ganglion cells evolved to subserve color vision, they should be absent in strepsirhines. We tested this hypothesis in a nocturnal strepsirhine, the greater bush baby Otolemur. The retinal ganglion cells were labeled with the lipophilic tracer Dil and the results show that bush babies have P/midget and M/parasol cells similar to those found in the peripheral retinas of anthropoids. A number of studies have shown that the P and M pathways of bush babies share many similarities with those of anthropoids, and our results show that the same is true for their retinal ganglion cells. These results support the hypothesis that the P system evolved prior to the emergence of red-green color opponency.     

MST-16, a novel derivative of bis(2,6-dioxopiperazine), synergistically enhances the antitumor effects of anthracyclines

OBJECTIVE: The aim of this study was to evaluate whether toluene, like many other organic solvents and solvent mixtures, could impair color vision. SUBJECTS AND METHODS: We investigated color vision impairment in three groups of workers, two groups occupationally exposed to toluene and a nonexposed group. The first exposed group, group E1, comprised 41 workers (median value of toluene in air 35.00 ppm, range 11.3-49.3 ppm) and the second exposed group, group E2, comprised 32 subjects (median value of toluene in air 156.00 ppm, range 66.0-250.0 ppm). The nonexposed group, group NE, comprised 83 subjects. Color vision was evaluated by the Lanthony D-15 desaturated test according to Verriest's classification: type I, loss in the red-green range; type II, loss in the blue-yellow and red-green ranges, and type III, loss in the blue-yellow range. Subjects were classified as dyschromates if specific acquired loss was determined in at least one eye. In both exposed groups, exposure was evaluated by measurement of the concentration of toluene in the ambient air and in the blood. In group E2, level of hippuric acid and orthocresol in urine after the work shift were also determined. The Mann-Whitney U-test, t-test, chi 2-test, and Spearman's rank correlation and multiple regression analysis were used for statistical analysis. RESULTS: Type III dyschromatopsia was detected in all groups examined: 26.6% of the workers in group NE, 31.7% of those in group E1, and 50% of those in group E2. As many as 15.6% of the workers in group E2, 4.8% of those in group E1, and only 1.2% of those in group NE had type II dyschromatopsia. A statistically significant difference in the prevalence of total dyschromatopsia (type III + type II) was established among the three examined groups together (chi 2 = 14.13; df = 2; P < 0.01), between group E2 and group E1 (chi 2 = 4.96; P < 0.05), and between group E2 and group NE (chi 2 = 12.50; P < 0.005), whereas no significant difference was found between groups E1 and NE. Type III dyschromatopsia was significantly correlated with age in group NE (P < 0.01) and in group E1 (P < 0.005). In group E2, both type II (P < 0.05) and type III dyschromatopsia correlated with toluene in ambient air and with the duration of exposure to toluene (both P < 0.005). In group E2, total dyschromatopsia correlated significantly with toluene in ambient air and in blood (both P < 0.05) as well as with hippuric acid in urine after the work shift (P < 0.001). CONCLUSION: This study suggests that toluene can impair color vision.     

Duction ranges in normal probands and patients with Graves'' ophthalmopathy, determined using the Goldmann perimeter

University students (111, both male and female) were screened for red-green color deficiency using projected 35 mm slides reproduced from Ishihara and H-R-R color plates. Ishihara and H-R-R color plates were tested in the same individuals at a second setting and the responses compared: 6.3% of the students were identified as color deficient by the Ishihara and 80.2% by the H-R-R projected slides while 5.4% were designated color blind by the Ishihara plates and 4.5% by the H-R-R plates. The sensitivity of both screening systems was 100%; the specificity of the Ishihara slides was 98.1% compared to only 20.8% for the H-R-R. The 9.8% prevalence of red-green deficiency detected by the Ishihara plates and 8.2% by the H-R-R plates for males is similar to the 6 to 9% frequency found for Caucasian males in other population studies. Within rigid guidelines, projected color slides have potential usefulness as a screening method for detecting individuals with red-green color deficiencies.     

Color vision in horses (Equus caballus): Deficiencies identified using a pseudoisochromatic plate test.

In the past, equine color vision was tested with stimuli composed either of painted cards or photographic slides or through physiological testing using electroretinogram flicker photometry. Some studies produced similar results, but others did not, demonstrating that there was not yet a definitive answer regarding color vision in horses (Equus caballus). In this study, a pseudoisochromatic plate test--which is highly effective in testing color vision both in small children and in adult humans--was used for the first time on a nonhuman animal. Stimuli consisted of different colored dotted circles set against backgrounds of varying dots. The coloration of the circles corresponded to the visual capabilities of different types of color deficiencies (anomalous trichromacy and dichromacy). Four horses were tested on a 2-choice discrimination task. All horses successfully reached criterion for gray circles and demonstration circles. None of the horses were able to discriminate the protan-deutan plate or the individual protan or deutan plates. However, all were able to discriminate the tritan plate. The results suggest that horses are dichromats with color vision capabilities similar to those of humans with red-green color deficiencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Central areolar choroidal dystrophy

Three members of a family with central areolar choroidal dystrophy showed the early and late stages of this disorder. The youngest affected was a 12-year-old girl who exhibited decreased vision, a red-green dyschromatopsia, and mild granularity of the macula with a diffuse foveal reflex. A discrete focal loss of choriocapillaris in the macula was seen on fluorescein angiography. This indicates that choriocapillaris atrophy is an early finding in this disease.     

Separate colour-opponent mechanisms underlie the detection and discrimination of moving chromatic targets

Current opinion holds that human colour vision is mediated primarily via a colour-opponent pathway that carries information about both wavelength and luminance contrast (type I). However, some authors argue that chromatic sensitivity may be limited by a different geniculostriate pathway, which carries information about wavelength alone (type II). We provide psychophysical evidence that both pathways may contribute to the perception of moving, chromatic targets in humans, depending on the nature of the visual discrimination. In experiment 1, we show that adaptation to drifting, red-green stimuli causes reductions in contrast sensitivity for both the detection and direction discrimination of moving chromatic targets. Importantly, the effects of adaptation are not directionally specific. In experiment 2, we show that adaptation to luminance gratings results in reduced sensitivity for the direction discrimination, but not the detection of moving chromatic targets. We suggest that sensitivity for the direction discrimination of chromatic targets is limited by a colour-opponent pathway that also conveys luminance-contrast information, whereas the detection of such targets is limited by a pathway with access to colour information alone. The properties of these pathways are consistent with the known properties of type-I and type-II neurons of the primate parvocellular lateral geniculate nucleus and their cortical projections. These findings may explain the known differences between detection and direction discrimination thresholds for chromatic targets moving at low to moderate velocities.     

Molecular genetic detection of female carriers of protan defects

Females heterozygous for congenital colour vision defects are of interest because they are believed to have cone photoreceptor ratios and cone photopigments that differ from normal. We describe a molecular genetic method to identify protan carriers that involves characterizing the genes that occur in the most upstream position in each of the X-chromosome photopigment gene arrays.     

Can clinical colour vision tests be used to predict the results of the Farnsworth lantern test?

Clinicians usually do not have access to a lantern test when making an occupational assessment of the ability of a person with defective colour vision to recognise signal light colours: they must rely on the results of ordinary clinical tests. While all colour vision defectives fail the Holmes Wright Type B lantern test and most fail the Holmes Wright Type A lantern, 35% of colour vision defectives pass the Farnsworth lantern. Can clinical tests predict who will pass and fail the Farnsworth lantern? We find that a pass (less than two or more diametrical crossings) at the Farnsworth Panel D 15 Dichotomous test has a sensitivity of 0.67 and specificity of 0.94 in predicting a pass or fail at the Farnsworth lantern test: a Nagel range of > 10 has a sensitivity of 0.87 and a specificity of 0.57. We conclude that neither the D 15 nor the Nagel Anomaloscope matching range are satisfactory predictors of performance on the Farnsworth Lantern.     

Integration of physical and semantic information in object processing

Physiological studies report independent processing pathways for form and colour information. A more-complex picture on human subjects has previously been reported. A sequential matching task was used that was based on a physical property of an object and in which semantic relations between stimuli were manipulated. Performance was affected by semantic information when matching was based on a property of the form of an object (its orientation, shape, or size). Effects of semantic information were eliminated when matching was based on the colour of a local part of an object but were found again when subjects matched pictures on the basis of the percentage of a colour integrated across the shape boundary. The results suggest independent selection mechanisms in vision in which selection by local colour can be based on inhibition of the form-processing pathway whilst processing of the global configuration of the form of an object activates automatically the identification process.     

Discrimination of duration ratios.

Trained pigeons to make discriminations on the basis of the ratio of two stimulus durations. A red light of one duration was followed by a green light of a different duration, with 900 red-green pairs intermixed over trials. A choice followed the red-green pair; a response to a green side key was reinforced if the red-green ratio was less than a criterion ratio, and a response to a red side key was reinforced if the ratio exceeded the criterion. Reinforcement depended on whether red or green was longer under the basic condition; in other conditions, however, reinforcement depended on whether one duration was two or four times longer than the other. Sensitivity was similar across conditions, for the basic shorter-longer rule, and for the more complex rule of one duration as two or four times the other. Most choices were made on the basis of the ratio relation between the two durations and according to Weber's law. These results extend the findings of L. R. Dreyfus et al (see record 1989-03920-001) and provide a new methodology for psychophysical scaling with animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)