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Results for “Color Perception Tests”

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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↗

PubMed1966

Stimulus control in fixed ratio matching-to-sample.

Pigeons were maintained on a fixed ratio (FR 9) schedule of reinforcement for correct matching-to-sample responses. Included in the test situation was a vertical array of lights, illuminated in relation to the successive steps of the fixed ratio. All five subjects showed regular decrements in matching errors across the sequence of unreinforced responses within the ratio cycle. In the form of a randomly introduced probe, the stimulus situation (array of lights) appropriate to having seven of the FR 9 steps already completed was occasionally introduced at the beginning of an FR cycle. Reinforcement followed the illumination of the two remaining lights by two correct matches. The number of errors in this probe condition was sharply lower than the errors characteristic of the first two steps of the basic FR 9.

Animals↗

PubMed1999

The oblique effect with colour defined motion throughout the visual field.

We assessed the extent of the oblique effect (OE) and the meridional orientation effect (MOE) for a chromatic motion task using red/green gratings throughout an 80 degrees visual field. Four different stimulus orientations were tested. Generally, sensitivity to chromatic motion decreased with increasing eccentricity regardless of the visual field meridian. Also, sensitivity was highest for horizontal or vertical gratings, thus supporting the presence of an OE rather than of a MOE. The strength of the OE varied between subjects, but was present from the fovea to 20 degrees of eccentricity. At 40 degrees of eccentricity, chromatic motion was always perceived but the grating orientation did not consistently influence chromatic motion sensitivity. The present study confirmed our previous results on chromatic motion sensitivity and isoluminance ratios throughout the visual field. In addition, our data show that the chromatic system can exhibit OEs at lower spatial frequencies than is observed for the achromatic system.

Analysis of Variance↗

PubMed2000

Parsing executive processes: strategic vs. evaluative functions of the anterior cingulate cortex.

Event-related functional MRI and a version of the Stroop color naming task were used to test two conflicting theories of anterior cingulate cortex (ACC) function during executive processes of cognition. A response-related increase in ACC activity was present when strategic processes were less engaged, and conflict high, but not when strategic processes were engaged and conflict reduced. This is inconsistent with the widely held view that the ACC implements strategic processes to reduce cognitive conflicts, such as response competition. Instead, it suggests that the ACC serves an evaluative function, detecting cognitive states such as response competition, which may lead to poor performance, and representing the knowledge that strategic processes need to be engaged.

Analysis of Variance↗

PubMed2003

Retinal function abnormalities in patients treated with vigabatrin.

OBJECTIVE: To evaluate central and peripheral retinal function in patients treated with vigabatrin, an antiepileptic drug associated with peripheral visual field constriction (VFC). METHODS: Six patients with epilepsy treated with vigabatrin as add-on therapy for at least 3 years were included in this observational case series. All patients underwent a clinical ophthalmologic examination, color vision testing, standard perimetry, and full-field and focal foveal cone electroretinography. Four patients, 3 of whom had VFC, completed specialized computerized static light- and dark-adapted perimetry. RESULTS: In 9 of 11 eyes tested, foveal cone electroretinographic amplitudes were at or below the lower limit of normal. Dark-adapted perimetry demonstrated abnormal rod-derived visual fields in the 3 patients with vigabatrin-attributed VFC, whereas rod-derived thresholds were within normal limits throughout the visual field in the patient who did not have VFC. CONCLUSIONS: Our results suggest that vigabatrin not only impairs peripheral cone-derived function as manifested by VFC but also affects foveal cone electroretinographic amplitudes and rod-derived visual fields. The clinical dilemma regarding the use of vigabatrin therapy is further complicated since central as well as peripheral visual function seems to be adversely affected.

Adolescent↗

PubMed1983

[Routine monitoring of patients treated with synthetic antimalarials].

Routine tests of visual acuity, and ocular fundus, angiography, and ERG examinations should be conducted regularly in patients receiving synthetic antimalarial drugs. Toxicity of these compounds is a current problem as 8 out of 81 patients being treated presented symptoms associated with ERG changes or macular lesions, and reduced visual acuity in some cases. There was a lack of correlation between ERG effects and the onset of macular disorders: one patient had marked macular changes and a normal ERG while another had a normal fundus and visual acuity but abolished ERG activity. Identical doses do not always produce the same effect and toxic symptoms have developed after a dosage ranging from 86 to 760 g. This suggests the existence of individual hypersensitivity.

Aged↗

PubMedDate not supplied

[The characteristics of the psychoautonomic status of patients with chronic combined diseases of the digestive organs].

Studied with the aid of the variational pulsimetry, adapted Lüscher's [correction of Leucher's] colour test, were the functional state of the vegetative nervous system, vegetative homeostasis, psycho-emotional state during both exacerbation and clinical remission of associated digestive diseases. Overall forty six children aged 11-14 were examined. The children were found out to be unlike in respect of the vegetative homeostasis. A contingent was identified with their compensatory and adaptive mechanisms failing to work adequately, and showing inability to react in an operative manner, high level of anxiety, emotional stress, psychic fatigue. Note is taken of the fact that in clinical remission the above parameters fail to return to normal whereupon an approach tailored to the individual is warranted toward treatment of the primary disorder to prevent relapse and chronization of the morbid process.

Adolescent↗

PubMed1995

The renin-angiotensin system--a possible neuromodulator in the human retina?

Morphology studies imply a possible contribution of the renin-angiotensin system (RAS) to neurotransmission in the mammalian retina. To investigate further the functional role of the RAS in the visual system of humans, we tested the effects of the angiotensin-converting enzyme (ACE) inhibitor Captopril (Capt; 25 mg) on electroretinogram (ERG) recordings, the cone flicker threshold (CFT), the FM-28-HUE test, and the psychophysical rod threshold in healthy volunteers. The parameters of renin, angiotensin, and blood pressure were controlled. We obtained the following results. First, Capt induced a significant decrease in amplitudes of the scotopic b-wave, oscillatory potentials, and the a-wave. The latency of responses to 30-Hz flicker was increased. Second, the CFT was reduced to a lower intensity, whereas the final rod threshold remained unchanged. These results are in accordance with previous immunocytochemical and electrophysiological data. They cannot be explained exclusively by the observed changes in systemic blood pressure. We conclude that the RAS may possibly be involved in retinal neurotransmission in humans in addition to its vascular effects.

Administration, Oral↗

PubMed1999

Phenotype in retinol deficiency due to a hereditary defect in retinol binding protein synthesis.

PURPOSE: To describe the phenotype caused by a retinol deficiency in a family with compound heterozygous missense mutations (Ile41Asn and Gly75Asp) in the gene for serum retinol binding protein (RBP). METHODS: The two affected sisters, 17 (BR) and 13 (MR) years old, were examined clinically and with perimetry, color vision tests, dark adaptometry, rod- and cone-isolated electroretinograms (ERGs), multifocal ERGs, electrooculograms (EOGs), and laboratory tests. RESULTS: There were no complaints besides night vision problems and no history of systemic disease. Visual acuity was reduced to 20/40 (BR) and 20/25 (MR). Anterior segments were normal except for a discrete iris coloboma. Both patients showed a typical "fundus xerophthalmicus," featuring a progressed atrophy of the retinal pigment epithelium. Dark adaptation thresholds were elevated. In the scotopic ERG, only reduced mixed responses were recordable. The photopic ERG was reduced in BR and normal in MR; implicit times were highly (BR) to slightly (MR) elevated. There was no (BR) to little (MR) light reaction in the EOG. All-trans retinol levels were 0.19 microM and 0.18 microM (normal range, 0.7-1.5 microM) for BR and MR, respectively, and did not increase in a dose-response test. RBP was below detection threshold, and retinyl esters were normal. CONCLUSIONS: Both affected siblings had no detectable serum RBP, one sixth of normal retinol levels, and normal retinyl esters. The retinal pigment epithelium was severely affected, but besides acne there were no changes to other organs. This gives evidence for an alternative tissue source of vitamin A, presumably retinyl esters from chylomicron remnants. The normal retinol levels in the tear fluid explain the lack of xerophthalmia. However, considering the role of RBP in the tear fluid and, during development, in the yolk sac there is also evidence that there are organ-specific RBP forms not affected by the genetic defect.

Adolescent↗

PubMed1992

[Changes in color differentiation using the 100-Hue Test. II. The score for basic colors of the spectrum in relation to age].

The author investigated changes of colour sensitivity of red, green and blue, using the FM 100-hue test. For examination healthy subjects without hypertension and diabetes and with a normal ophthalmological finding and normal functions were selected. In six age groups (21-80 years) 240 male and female eyes were examined. In the youngest age group there was greatest proportion of errors in the blue area, less in the green area and the least in the red area. A more detailed analysis revealed that the greatest rate of errors was in the blue-green area. With advancing age the number of errors in the areas of the basic colours increase and at the same time differences between differentiation of red, green and blue decrease. In the age group above 71 years no differences were found in the score of errors in the area of basic colour.

Adult↗

PubMed1993

Priming effect in a color discrimination task.

Two experiments were run to test whether the automatic coding of colors generates priming effects. Subjects were tachistoscopically presented a series of prime-target sequences. The prime stimulus could be either a red, green, or black circular dot, followed by a red or green annular ring (target). The role of automatic and conscious mechanisms was investigated in Exp. 1 by manipulating the predictive validity of the prime stimuli (80%, 50%, 20%), keeping constant the value of stimulus-onset asynchrony (350 msec.). Analysis showed priming effects even in the low predictive condition, where no conscious expectations could be activated. In Exp. 2, three different values of stimulus-onset asynchrony were used, 150, 350, and 2100 msec. Priming effects were obtained in the short and medium stimulus-onset asynchrony condition but not in the long one. Over-all, the data of both experiments produce converging evidence which indicates that the automatic elaboration of colored stimuli may produce priming effects.

Adult↗

PubMed1993

A second box-end scoring artifact in the Farnsworth-Munsell 100-hue test.

PURPOSE: To investigate and describe a hitherto unreported scoring artifact in the Farnsworth-Munsell 100-hue Test, arising from the grouping of the caps into four boxes, which causes caps near the ends of a box to score less than caps near the center of a box. This artifact is in addition to a previously reported one, which causes caps near the end of a box to score more than caps in the center of the box. METHODS: Two different statistical simulations were used to generate synthetic cap sequences, which were scored in the normal way. RESULTS: For error scores less than about 500, the new artifact, which depresses scores at the ends of boxes, was found to dominate the pattern of scores. CONCLUSION: The existing published correction for the box-end scoring artifact is inappropriate for scores less than about 500, and therefore should be applied cautiously.

Artifacts↗

PubMedDate not supplied

Colorimetric analysis of four editions of the Hardy-Rand-Rittler pseudoisochromatic tests.

At the Göttingen meeting of the International Colour Vision Society, I reported on a comparison of the second edition of the American Optical Hardy-Rand-Rittler Pseudoisochromatic plates (AO HRR) with the Richmond Products third edition of the same test and concluded that the chromaticities were exceptionally poorly matched and that the new edition was a "pale imitation of the real thing" (unpublished). This conclusion led to our abandoning a clinical trial. In 2002, Richmond Products has published a fourth edition and, in 2003, Waggoner has published a modified HRR with additional (Ishihara style) plates and the tetartan confusion figures removed. As a precursor to any clinical trial, the colors used in the plates have been measured and comparisons drawn between the four editions. While the two most recent editions much more closely resemble the original AO HRR and the chromaticities are much better aligned on the dichromatic confusion lines, the excitation purities (and therefore the degree of difficulty) of the plates are less well matched in the Richmond Products editions. In addition, there is a significant degree of metamerism in the third edition and Waggoner edition that makes variations in illuminant more critical to performance.

Color Perception↗

PubMed2005

A study of hue identification in the hue circle of the HSB color space.

The purpose of the present research was to explore the relationship between the sensory difference in hues in the hue circle of the HSB color space and their included angles in identification tasks. In the experiment, the two colors were presented separately, and the test subjects judged whether the two colors were the same or different. Five hues, called Standard Stimulus Hues and the most saturated colors in the hue circle of the HSB color space, were discussed. These are hue 0 degrees, hue 72 degrees, hue 216 degrees, and hue 288 degrees in the HSB color space. The Just Identifiable Angle refers to the included angle between a specific standard hue and the hue which cannot be identified separately and which is the furthest from the standard hue in the hue circle of the HSB color space. Analysis gave a significant main effect of standard hue. The Just Identifiable Angles for hue 72 degrees and hue 288 degrees did not differ significantly, but their Just Identifiable Angles were discernibly lower than those for the other three hues. The Just Identifiable Angle of hue 144 degrees was significantly lower than those for hue 0 degrees and hue 216 degrees. In addition, the Just Identifiable Angle for hue 0 degrees was noticeably larger than the one for hue 216 degrees, so the final outcome might show that the Just Identifiable angles of the standard hues are not equal.

Adolescent↗

PubMed2001

Phenotypic subtypes of Stargardt macular dystrophy-fundus flavimaculatus.

OBJECTIVE: To determine if phenotypic subtypes exist in Stargardt macular dystrophy-fundus flavimaculatus (SMD-FFM). METHODS: A cross-sectional study of 63 patients with autosomal recessive SMD-FFM was undertaken. The age of onset, duration of symptoms, visual acuity, and clinical features on fundus examination, color fundus photographs, and fundus autofluorescence images were recorded. Electrophysiological tests, including pattern, focal, and full-field electroretinogram (ERG), electro-oculogram, and color-contrast sensitivity measurement, were also performed. RESULTS: Based on electrophysiological attributes (ERG), patients with SMD-FFM could be classified into 3 groups. In group 1, there was severe pattern ERG abnormality with normal scotopic and full-field ERGs. In group 2, there was additional loss of photopic function, and in group 3, there was loss of both photopic and scotopic function. Differences in scotopic or photopic function among groups were not explained on the basis of differences in age of onset or duration of disease. CONCLUSIONS: Patients with SMD-FFM can be classified into 3 groups based on the absence or presence of generalized loss of either photopic or photopic and scotopic function. It appears that these 3 groups may represent distinct phenotypic subtypes in SMD-FFM.

Adult↗

PubMed1989

Colour vision in a family with Sorsby's dystrophy.

Fraser & Wallace (1971) investigated a family with Sorsby's dystrophy, and found a high prevalence of a mild red-green colour deficiency. Using a battery of tests, I re-examined the colour vision of members of the family at risk of developing the disease. I conclude that the mild colour vision defect is classical sex linked recessive deuteranomaly occurring adventiously in the family; its high prevalence is due to its being introduced by at least 3 persons marrying into the family. Two alternative hypotheses of the colour vision deficiency are that it is an acquired disorder which is a prodromal sign of the dystrophy or that it is inherited in an autosomal dominant manner. However, these hypotheses were rejected because the colour vision deficiency had the characteristics of a typical sex linked disorder. These findings emphasize that it is important to exclude any co-existing inherited colour vision defect when defining the clinical features of any retinal dystrophy by careful evaluation of unaffected family members.

Adolescent↗

PubMed1984

Temporal sensitivities related to color theory.

Sensitivities of color-normal observers to temporal variations in stimulus luminance and chromaticity were measured for sine-wave stimuli between 1.5 and 20 Hz. Clear differences were found in observers' sensitivities to isochromatic luminance variations and to isoluminous chromaticity variations for wavelength pairs selected to test temporal discriminability along the red-green and yellow-blue dimensions, respectively. Despite interobserver differences in individual red-green functions, a given observer's sensitivity could be described by a single curve shape specific to that observer. Overall sensitivity for yellow-blue was less than that for red-green for all observers. Differences in curve shape between red-green and yellow-blue functions are found for individual observers, but group averages reveal that the differences are not systematic. Red-green temporal sensitivity is largely unaffected by adapting backgrounds in red-green equilibrium but is attenuated at low frequencies by nonequilibrium backgrounds of the same luminance. Isochromatic luminance sensitivity is largely independent of our adapting backgrounds, but heterochromatic luminance modulation functions undergo expected changes in form.

Color↗

PubMedDate not supplied

Prediction of diabetic retinopathy from clinical variables and color vision data.

Predictions about the onset of retinopathy in 295 diabetic patients, all originally having no evidence of retinopathy, have been made in a longitudinal study over 7 yr. Out of many color vision tests and clinical variables, the best individual predictor was a measure of yellow-blue discrimination, using an anomaloscope. The other predictors of significance were the degree of blood glucose control and the duration of diabetes. Although the predictions from a linear logistic model were significant in classifying the diabetic subjects into those whose fundus will remain normal and those in whom it will develop retinopathy, the number of misclassifications was substantial. An examination of the goodness of fit between the data and the model suggested a criterion value (P) of around P = 0.3 for the probability that a patient develops retinopathy. At this value, the probability of being normal for an individual classed as normal was 0.82, and the probability of developing retinopathy for an individual classed as having retinopathy was 0.54.

Adult↗