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PubMed1998

Rods affect S-cone discrimination on the Farnsworth-Munsell 100-hue test.

Rod influence on hue discrimination was assessed by the Farnsworth-Munsell 100-hue test. Rod influence was taken as the difference in error scores obtained after complete dark adaptation and during the cone plateau at three mesopic (23, 9, 3 td) and one standard (158 td) light level. On the FM 100, rods produced a differential discrimination loss along a tritan axis as compared with a red-green axis without any bias toward a rod confusion axis. Rods appear to impair discrimination mediated by S-cone pathways, which at moderate levels of illumination can differentially elevate tritan errors on the FM 100.

Adult↗

PubMed1995

[Personal computer used in visual function screening].

BACKGROUND: The number of medical screenings is increasing. This fact is specially pronounced in the field of occupational health. Due to restricted financial resources and limitations in time there is a need for rationalisation in medical screenings. MATERIALS AND METHODS: Possible uses of personal computers (PC) enabling organisational and financial benefits in medical screenings are suggested. By means of a test for colour-blindness it is shown how unfavourable technical conditions may be by-passed. RESULTS AND DISCUSSION: Rationalisation in medical screenings can be achieved when using the PC as a multi-functional screening-device as well as an expert system, measuring apparatus and as a communication-device. Due to a lack of literature it is difficult to discuss possible effects of technical differences between PC-based screenings of visual functions and screenings where "traditional". Reliability, sensitivity and validity is insufficiently investigated for many of the commercial available screening-devices based on a PC.

Color Perception Tests↗

PubMedDate not supplied

Color constancy in natural scenes with and without an explicit illuminant cue.

Observers can generally make reliable judgments of surface color in natural scenes despite changes in an illuminant that is out of view. This ability has sometimes been attributed to observers' estimating the spectral properties of the illuminant in order to compensate for its effects. To test this hypothesis, two surface-color-matching experiments were performed with images of natural scenes obtained from high-resolution hyperspectral images. In the first experiment, the sky illuminating the scene was directly visible to the observer, and its color was manipulated. In the second experiment, a large gray sphere was introduced into the scene so that its illumination by the sun and sky was also directly visible to the observer, and the color of that illumination was manipulated. Although the degree of color constancy varied across this and other variations of the images, there was no reliable effect of illuminant color. Even when the sky was eliminated from view, color constancy did not worsen. Judging surface color in natural scenes seems to be independent of an explicit illuminant cue.

Analysis of Variance↗

PubMed1981

Digoxin retinal toxicity. Clinical and electrophysiological evaluation of a cone dysfunction syndrome.

A 70-year-old man was studied both during and after resolution of clinical digoxin toxicity using color vision tests, ganzfeld electroretinography and electro-oculography. Concomitant administration of quinidine sulfate probably contributed to digoxin toxicity. Abnormalities in color vision and subnormal amplitude and prolonged implicit time for cone-mediated electroretinogram (ERG) responses suggested a cone dysfunction syndrome. The electro-oculographic light-to-dark ratio during clinical toxicity was high for our laboratory, but this is probably normal. Notable improvement was seen in color vision and the ERG after cessation of digoxin therapy. Inhibition of sodium-potassium adenosine triphosphatase by digoxin probably influences normal uptake of extracellular potassium by Müller's cells and other retinal neurons. This mechanism may contribute to subnormal, prolonged cone-mediated ERG responses in retinal toxic reactions from cardiac glycosides.

Adaptation, Ocular↗

PubMed1988

D-15 performance with short wavelength absorbing filters in normals.

Short wavelength absorbing filters (SWAF's) have become very popular in the prescription and commercial sunglass markets. Like other chromatic filters SWAF's have the potential to alter color vision. Performance on the Farnsworth Panel D-15 (D-15) test was measured to determine whether any of 4 popular SWAF's, in the form of sunglasses, produced color vision changes in 22 color normal adults. Using standard illuminant C, observers were tested under the following conditions: wearing no filter, a 1.0 log unit neutral density filter (NDF), or one of the following SWAF's: Corning CPF 550; NolR Amber 40%; Blu Blocker; and Vuarnet 4006. In addition, the Vuarnets were tested outdoors in shaded daylight to determine the effects of increased illumination. The NDF served as the control and had no effect on D-15 performance. Compared to it, only the Blu Blockers and Vuarnets affected D-15 cap arrangements for these SWAF's significantly. Blu Blocker error patterns had no predominant axis, whereas the predominant axis of errors in both Vuarnet conditions was tritan. Results of quantitative analysis performed on three factors confirmed these findings and indicated the Blu Blockers and Vuarnet SWAF's caused moderate and moderate-to-severe levels of color confusion, respectively. Increasing the illumination level improved performance with the Vuarnets, but it remained significantly outside the normal range.

Adult↗

PubMed2006

Transcaruncular orbital decompression: an alternate procedure for Graves ophthalmopathy with compressive optic neuropathy.

PURPOSE: To study the efficacy of transcaruncular orbital apex decompression for Graves ophthalmopathy with compressive optic neuropathy nonresponsive to pulse corticosteroids. DESIGN: Retrospective, interventional case series study. METHODS: From August 1999 to November 2003, transcaruncular orbital decompression was performed in 22 consecutive Graves ophthalmopathy patients with compressive optic neuropathy refractory to pulse corticosteroids. The average period of corticosteroid treatment was 16.1 +/- 5.2 days. Main outcome measures were preoperative and postoperative best-corrected vision, Hertel exophthalmometry, 100-hue color sensation test, visual evoked potential, visual field, and new-onset diplopia. RESULTS: Visual acuity improved significantly from 1.08 +/- 0.24 logarithm of minimal angle of resolution (logMAR) preoperatively to 0.29 +/- 0.18 logMAR postoperatively (P < .0001). Average improvement in retinal sensitivity was 9.4 +/- 8.2 dB, in P(100) value of visual evoked potential was 27.5 +/- 20.1, and in "total errors" of the 100-hue test was 309.9 +/- 214.3 after surgery. Average retroplacement effect was 3.7 +/- 1.6 mm. Statistical analysis showed significant differences between preoperative and postoperative measurements for all above parameters (P < .0001). New-onset diplopia occurred in 38% of patients. There were no complications specifically attributable to the transcaruncular technique. CONCLUSIONS: The transcaruncular approach offers access to the medial and inferior wall for orbital apex decompression in Graves ophthalmopathy patients with compressive optic neuropathy refractory to pulse corticosteroids. Advantages over other approaches included no external scar, less damage to adjacent tissue, and wide exposure to the entire medial wall.

Adult↗

PubMed2004

Oligocone trichromacy: a rare and unusual cone dysfunction syndrome.

AIM: To describe the phenotype of a case series of six patients with oligocone trichromacy. METHODS: The six affected individuals underwent an ophthalmological examination, electrophysiological testing and detailed psychophysical assessment. RESULTS: All six affected patients had a history of moderately reduced visual acuity (6/12 to 6/24) from infancy, not improved by full spectacle correction. They complained of mild photophobia and they were not aware of any colour vision deficiency. They had no nystagmus and fundi were normal. Electrophysiological testing revealed either absent/profoundly reduced cone flicker responses or preserved but delayed and mildly reduced flicker responses. Colour vision was found to be within normal limits, but some patients showed mildly elevated discrimination thresholds along all axes. CONCLUSION: The largest case series to date of patients with oligocone trichromacy is presented. The electrophysiological findings suggest that there may be more than one disease mechanism. The mode of inheritance is likely to be autosomal recessive, and while previous reports have suggested that this disorder is stationary, in one of these families there is clinical evidence of progression.

Adolescent↗

PubMed1999

Evidence for the stochastic independence of the blue-yellow, red-green and luminance detection mechanisms revealed by subthreshold summation.

We investigated the manner in which the outputs of the three postreceptoral mechanisms (red-green, blue-yellow and luminance) combine to determine contrast threshold. We used a subthreshold summation paradigm to test whether the combination of the postreceptoral mechanism outputs could be described by a probability summation model which assumes stochastic independence of the mechanisms, and determined the best fitting summation exponent. Stimuli were Gaussian enveloped 1 c/d sinusoidal gratings represented in a 3D cardinal space transformed from cone contrast axes, and normalized to detection threshold. The use of this space avoids the presence of elongated threshold contours, allowing a reliable model fit to include the less sensitive blue-yellow and luminance mechanisms. Our results were well fitted by the probability summation model and hence support the underlying stochastic independence of the three postreceptoral mechanisms.

Chi-Square Distribution↗

PubMed1991

Color pattern-reversal visual evoked potential in eyes with ocular hypertension and primary open-angle glaucoma.

Color pattern-reversal visual evoked potential testing was performed in 99 normal eyes, 27 eyes with ocular hypertension and 30 eyes with primary open-angle glaucoma with the use of black-white, black-red and black-blue color checkerboard stimuli. The P1 wave peak time and amplitude of the eyes with ocular hypertension and glaucoma were significantly different from those of age-similar normal eyes, especially on the black-red and black-blue checkerboards (p less than 0.001). The differences between the ocular hypertensive and glaucomatous eyes were of less significance. The P1 peak time difference between black-white and black-red checkerboards may serve as an important parameter in the early diagnosis of glaucoma.

Adolescent↗

PubMed2004

A new interference score for the Stroop test.

A New interference calculation method for the Stroop test was developed based upon a neuropsychological model of the suppression of word reading in favor of color naming. Polynomial regression equations show a significant relationship between word reading and the New interference score that closely fits the underlying prediction of the New model, while the Golden [Stroop Color and Word Test, Stoelting Co., IL, Wood Dale, 1978] model (Old) produces only a random relationship. Constructs of developmental maturation and lateralized brain damage are supported by the New but not the Old method. The New compared to the Old method also gives a significant reduction in scores in a small sample of demented patients. It would be advisable to use this New model in both cognitive and neuropsychological comparisons of different lesions or different stimulus and response demands. The New model will also help promote finer clinical inferences when an understanding relative to the patient's own baselines is necessary.

Adolescent↗

PubMed1999

The spatial tuning of color and luminance peripheral vision measured with notch filtered noise masking.

We have measured the spatial bandwidths of the bandpass red-green chromatic and luminance mechanisms at four locations in the nasal visual field (0, 10, 20 and 30 degrees) using a method of notch filtered noise masking which effectively removes the artifact of off-frequency looking for our stimuli. Detection thresholds were measured for luminance or isoluminant red-green Gaussian enveloped test gratings of 0.5 cpd embedded in 1/f noise. Firstly, thresholds were obtained as a function of increasing noise spectral density and were fitted using a standard noise masking model. These results support the existence across the visual field of independent, red-green chromatic and luminance mechanisms with similar sampling efficiencies. Secondly, we measured thresholds in notch filtered noise as a function of notch width and derived the spatial bandwidth of the detection mechanism. We find both color and luminance mechanisms have similar bandwidths which remain virtually constant across eccentricity. These results indicate strong overall similarities between the early processing of color and luminance vision, and lend support to the role of color as an 'intrinsic image' in spatial vision. The results are discussed in the light of the anchored channel and shifting channel models of peripheral contrast sensitivity and pattern detection.

Color Perception↗

PubMed2002

Colour contrast sensitivity in ocular hypertension. A five-year prospective study.

PURPOSE: To evaluate a peripheral colour contrast sensitivity test as a tool for early diagnosis of glaucoma in a five-year prospective study. PATIENTS AND METHODS: Peripheral colour contrast sensitivity was measured with a computer graphics system developed by Arden et al. The test colours were varied along the protan, deutan and tritan colour confusion axes on a scale from 0 to 100 percentage units. Fifty-five ocular hypertensive (OH) patients examined with the colour contrast test, stereoscopic photography of the optic discs, and measurements of visual fields (Humphrey 24-2 glaucoma hemifield test (GHT)) in 1994, were re-examined after five years. RESULTS: Ten patients were 'outside normal limits' in the GHT at follow-up. This group of 10 patients did not differ in colour contrast thresholds at the test in 1994 from the 45 who were still 'normal' (or 'borderline') at follow-up. Neither were there proportionally more patients with GHT 'outside normal values' for the patients with high colour contrast thresholds (> 30% units) in 1994 regarding any of the three colour axes. As judged from patient files, 27 patients had developed glaucoma during follow-up. Although there were differences between these 27 glaucoma patients and the remaining OH group at the colour contrast test in 1994, these differences did not reach statistical significance for any of the colour axes (largest difference in the tritan axis: 6.2% units, P = 0.0745). At follow-up, however, there was a significant difference in colour contrast for the protan axis between the clinical glaucoma group and the OH group (6.7% units, P = 0.0105). CONCLUSION: The method used for colour contrast measurement did not reveal glaucomatous changes before conventional perimetry (Humphrey 24-2, GHT). Neither did it predict the patients who, in our clinic, subsequently developed glaucoma during a five-year period. A change over time in colour contrast in the protan axis for an OH patient may, however, indicate glaucoma development.

Color Perception↗

PubMed1982

Spectral sensitivity and color discrimination changes in glaucoma and glaucoma-suspect patients.

Color vision changes may occur early in the course of glaucoma and may precede visual field loss. Glaucoma suspects, having raised intraocular pressure and no diagnostic optic nerve head or visual field changes, may also have color vision loss. Unfortunately, the instruments used in the studies that have demonstrated these color vision changes were not feasible for routine clinical use; likewise, the studies did not carefully control for the effects of small pupil size and age or did not point to the underlying mechanisms responsible. We studied 19 glaucoma patients, 19 glaucoma suspects, and age-matched controls for each group by means of the Farnsworth D-15 panel test, a desaturated version of the D-15 test, and by measures of spectral increment threshold. Minor modifications of the Farnsworth D-15 panel test produce highly significant differentiation of glaucoma and glaucoma-suspect patients from age-matched normal groups. Further, spectral increment thresholds, with a two-degree spectral target flashed at either 1 or 25 Hz on a bright white background, show that both achromatic and chromatic sensitivity are significantly reduced when compared with their age-matched normals. Pupil size does not seem to be a significant factor. These results suggest that the function of two different ganglion cell populations is affected in glaucoma and that glaucoma may produce functional loss in the central foveal area earlier in the disease process than previously believed.

Adolescent↗

PubMed1982

Brightness of equal-luminance lights.

The brightness of lights defined by heterochromatic flicker photometry as being of equal luminance was determined by direct comparison with a white standard. Stimuli included mixtures of white and colored lights. Eight different colorimetric purities were tested for each of eleven primaries. Adaptation to a known white was maintained. Resulting brightnesses were expressed in terms of the ratio of the amount of light required for a brightness match to the amount required for a flicker photometric match (B:F). B:F ratios varied with the primary, being largest for red and blue primaries. The variation of B:F ratio with colorimetric purity differed depending on the primary, although for any given dominant wavelength the highest-purity stimulus always had the largest B:F ratio. The data qualitatively exclude a number of simple models of brightness generation.

Color↗

PubMed1996

Visual field loss following vitrectomy for stage 2 and 3 macular holes.

AIM: To describe the phenomenon of peripheral field loss following routine pars plana vitrectomy for stage 2 and 3 full thickness macular hole and to investigate the underlying mechanism. METHODS: Five patients, who reported peripheral field defects after apparently uncomplicated vitrectomy, posterior cortical vitreous peeling, and perfluoropropane (C3F8) gas tamponade, were studied retrospectively with slit-lamp biomicroscopy, automated and kinetic perimetry, fundal fluorescein angiography, focal electroretinography (ERG), and colour contrast sensitivity (CCS) testing. RESULTS: All five patients, who were between 50 and 73 years of age, reported an inferotemporal field defect following resolution of the intraocular gas bubble. In all eyes, the scotomata encroached to within 20 degrees to 30 degrees of fixation and to within 5 degrees to 15 degrees of the blind spot. In one eye, a partial altitudinal component was evident. All scotomata subsequently remained stable and three eyes developed subtle segmental nasal disc pallor and nerve fibre loss corresponding to the field defect. CCS testing revealed absent colour contrast in the scotomatous area, in the presence of a preserved focal quadrantic flash ERG, compared with normal CCS protan thresholds and focal ERGs in unaffected quadrants, indicating preserved outer retinal function in the area of the scotoma. CONCLUSIONS: These observations support the hypothesis that field defects occur as a result of retinal nerve fibre layer damage. It is proposed, on the basis of intraoperative observations and other evidence, that the most likely site of nerve fibre damage is at the nasal portion of the optic nerve rim or peripapillary retina, probably due to traction during cortical vitreous peeling.

Aged↗

PubMed1993

The normal color vision evaluated with FM 100-hue test.

One hundred and twenty normal subjects (240 eyes) aged from 10 to 69 were tested with FM 100-hue test. They were divided into 6 groups according to their age. It was shown that there were no statistically significant difference in the total error score (TES) between the males and females or between the right and left eyes, but there existed some relationships between the TES and age. The total error score (TES) was the lowest in the 20-29 age group and increased gradually with aging. The analysis of the partial error score (PES) in each age group showed that the PES was the lowest in 20-29 age group and that the larger PES appeared around the axis of titan with age increasing.

Adolescent↗

PubMed2000

Neuropsychological functions in idiopathic occipital lobe epilepsy.

PURPOSE: Despite the benign prognoses of idiopathic partial epilepsies, particularly regarding the response of seizures to treatment, some evidence now exists that patients with such disorders may have subtle neuropsychological deficits. This study was designed to investigate several modalities of neuropsychological functioning in a group of 21 patients, ranging from 6 to 14 years of age, with idiopathic occipital lobe epilepsy (IOLE). The case patients were compared with 21 healthy controls matched for age, sex, and socioeconomic status. METHODS: A battery of age-appropriate neuropsychological tests was administered individually to all the participants. Tests were chosen on the basis of age-appropriate norms, their ability to represent a wide variety of functional domains, and their appropriateness in a cross-cultural setting. The tests were selected to measure functioning in six domains: intellectual functioning, attention, memory, academic achievement, visual-motor functioning, and executive functioning; some were further subdivided by their verbal-versus-visual modality of functioning. RESULTS: The results revealed no significant difference in basic neurophysiological functions between the patient and control groups, although the case patients' performance scores were lower in attention (p < 0.01) and memory (p < 0.01), as well as in intellectual functioning (p <.05). CONCLUSIONS: The possibility of subtle cognitive deficits in IOLE patients should always be considered, though further studies are necessary to elaborate their precise and long-term effects.

Achievement↗

PubMed1995

[Effect of pharmacotherapy of affective disorders on the psycho-semantics of alcoholic patients].

90 alcoholic patients (II stage of alcoholism) with secondary affective disorders (anxiety, depression) were divided into 4 groups. The patients of the first group received the GABA receptor ligand baclofen during 3 weeks. Sybazon preparation was used in the second group, while the patients of the third group were treated with amitriptyline. Placebo was applied in the forth group. The clinical psychological tests demonstrated that all drugs caused quite effective relief of affective disorders. Psychosemantic tests application showed that the pharmacotherapy caused positive changes in patients of 1-3 groups. These changes touched on both system of personal estimations and relations of personality to himself and to the world around i.e. psychosemantic sphere. Such changes in psychosemantic sphere were not observed in the 4-th group of patients (placebo). Besides it was revealed that each drug caused some specific changes in psychosemantic sphere. The result obtained were supposed to have some theoretical value in comprehension of brain-psychics relations as well as the applied significance for adequate choice of affective disorders pharmacotherapy of alcoholic patients.

Alcoholism↗