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Scanning laser densitometry in visual acuity loss of unknown origin.

AIM: To assess foveal cone photoreceptor function in patients with unexplained loss of central visual acuity. METHODS: Testing of foveal cone photoreceptor function was performed using scanning laser densitometry, colour matching (Rayleigh equation), and pattern electroretinography (ERG). Standard tests included full field ERG, electrooculography, visual evoked potentials, static perimetry, and fluorescein angiography. RESULTS: Decreased foveal cone photopigment density and abnormal pattern ERG were found in three patients. Results of colour matching were not unequivocal. CONCLUSION: Testing of foveal cone photoreceptor function using scanning laser densitometry may determine the location of pathological changes in certain patients with unexplained visual loss.

Adolescent↗

Visual acuity and colour vision tests--a preliminary report.

Results are reported of a preliminary survey of colour vision changes in fifteen patients with central serous retinopathy. Colour vision was monitored with the HRR plates, 100-hue test and Nagel anomaloscope. In those patients revealing an acquired dyschromatopsia the defect had a tritan-like response. However, diagnosis is made difficult because of the positively correlated trend between 100-hue error score and visual acuity.

Adult↗

Correlation between color vision scores and quantitative perimetry in suspected glaucoma.

The mean differential threshold, studied on the Octopus perimeter, and color vision, estimated by the Farnsworth-Munsell 100-Hue test, were studied in glaucoma suspects and patients with questionable early field defects. The results of both tests were significantly correlated. The color vision scores correlated with the central, paracentral, and midperipheral parts of the visual field. This result suggests that both functions are disturbed in glaucoma and that the disturbance may be present diffusely throughout the visual field.

Aged↗

Sensorial anomalies in strabismus. (suppression, anomalous correspondence, amblyopia).

Some concepts regarding suppression, anomalous correspondence and amblyopia are revised according to the sensorial findings obtainable from esotropic patients directly in casual seeing (with the aid of the striated glasses test) and by grading a sensorial dissociating effect (with the aid of a bar of optical filters). The following points are emphasized: 1. Suppression appears to be minimal in small angle strabismus where diplopia seems mainly to be avoided by an anomalous correspondence mechanism. On the contrary, suppression is the prevalent mechanism in large angle strabismus. 2. The anomalous correspondence mechanism may lead to a weak type of anomalous binocular vision which is easily interrupted by light optical filters or by dissociating tests. 3. The subjective space of patients with anomalous binocular vision resembles that of normal binocular vision in some aspects. 4. The development of amblyopia is interpreted in the light of these new concepts on suppression and anomalous binocular vision. 5. Postoperatively, anomalous correspondence rapidly re-adapts to the smaller angle deviation and may normalize if the deviation is completely eliminated. This is evident only in casual seeing; for a certain time, dissociating tests reveal the preoperative correspondence status. This behaviour of correspondence in casual seeing has led to attempts at normalizing anomalous correspondence by prism therapy. Newly observed sensotio-motorial obstacles, however, have been found to frequently hamper treatment in casual seeing.

Amblyopia↗

Color constancy and the functional significance of McCollough effects.

A central problem in visual perception concerns how humans perceive stable and uniform object colors despite variable lighting conditions (i.e. color constancy). One solution is to 'discount' variations in lighting across object surfaces by encoding color contrasts, and utilize this information to 'fill in' properties of the entire object surface. Implicit in this solution is the caveat that the color contrasts defining object boundaries must be distinguished from the spurious color fringes that occur naturally along luminance-defined edges in the retinal image (i.e. optical chromatic aberration). In the present paper, we propose that the neural machinery underlying color constancy is complemented by an 'error-correction' procedure which compensates for chromatic aberration, and suggest that error-correction may be linked functionally to the experimentally induced illusory colored aftereffects known as McCollough effects (MEs). To test these proposals, we develop a neural network model which incorporates many of the receptive-field (RF) profiles of neurons in primate color vision. The model is composed of two parallel processing streams which encode complementary sets of stimulus features: one stream encodes color contrasts to facilitate filling-in and color constancy; the other stream selectively encodes (spurious) color fringes at luminance boundaries, and learns to inhibit the filling-in of these colors within the first stream. Computer simulations of the model illustrate how complementary color-spatial interactions between error-correction and filling-in operations (a) facilitate color constancy, (b) reveal functional links between color constancy and the ME, and (c) reconcile previously reported anomalies in the local (edge) and global (spreading) properties of the ME. We discuss the broader implications of these findings by considering the complementary functional roles performed by RFs mediating color-spatial interactions in the primate visual system.

Animals↗

Multifocal electroretinographic evaluation of long-term hydroxychloroquine users.

OBJECTIVES: To observe the long-term effects of hydroxychloroquine sulfate on retinal electrical activity by multifocal electroretinography (mfERG) and to evaluate the regional variation of retinal dysfunction in subjects with hydroxychloroquine retinopathy. METHODS: Multifocal ERG with 103-hexagon stimulation was performed on 19 patients (36 eyes) treated with hydroxychloroquine for systemic lupus erythematosus, rheumatoid arthritis, or localized atypical scleroderma. Visual acuity testing, Amsler grid testing, and Ishihara color vision testing were also performed. In 2 of the patients, hydroxychloroquine was discontinued due to concerns about toxicity. Both of these patients had additional mfERG performed after discontinuation of medication. RESULTS: Twelve patients (19 eyes) had a normal response density in one or both eyes, including 6 patients (12 eyes) with a low lifetime dose (< or =438 g) of hydroxychloroquine who had normal response densities in both eyes. Eleven patients (17 eyes) had abnormal response densities in one or both eyes, and 2 of these patients (4 eyes) had significant attenuation of response densities in almost the whole tested field; 4 patients had a normal mfERG result for one eye but had a slight decrease of response densities for the other eye. There were 4 patterns of abnormal mfERG amplitude change observed: (1) paracentral loss, (2) foveal loss, (3) peripheral loss, and (4) generalized loss. Implicit times were abnormal for pericentral responses in 3 patients. The results of color vision and Amsler grid testing were normal, except for one patient with a generalized loss pattern. In 2 subjects in whom hydroxychloroquine toxicity was suspected, response densities improved after termination of hydroxychloroquine. CONCLUSIONS: Long-term hydroxychloroquine use may be associated with mfERG abnormalities. The mfERG appears to detect retinal physiological change earlier than visual acuity testing, color vision testing, or Amsler grid testing can. The greatest value of the mfERG is in differentiating a retinal cause and, hence, providing important evidence for hydroxychloroquine toxicity, for whatever visual field loss is apparent on perimetry.

Adult↗

Changes of color vision in ocular hypertension.

Fifty-six ocular hypertension (OHT) patients were examined for 2-3 days in the Eye Clinic of Kuopio University Hospital. No glaucomatous changes were found. Twenty-seven of them were found to have several risk factors for developing glaucoma and medication was started. Twenty-nine of the patients did not show risk factors and had no medication. Color vision was examined with the Farnsworth-Munsell 100 (FM 100) hue test and Besançon anomalometer, later Color Vision Meter 712 at the beginning of the study and 3 years later. None of the 56 patients showed any glaucomatous changes after 3 years of the study. In the treatment group, the FM 100 test showed significantly (paired t-test, p = 0.004) improved error scores after 3 years. In the non-treatment group, 19 patients did not develop risk factors; they had no significant changes in the color vision results. In 10 patients of the non-treatment group, risk factors had developed with elevated intraocular pressure and medication was started for them after 3 years. Their color vision results in the blue anomalous quotient (AQ) of the anomalometer had significantly shifted to the blue part of the equation (paired t-test, p = 0.04). The other color vision results had not changed significantly. The significantly improved FM 100 scores in the treatment group could mean, that the treatment has a beneficial effect for the OHT eyes at risk for developing glaucoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Colour discrimination thresholds in Parkinson's disease: results obtained with a rapid computer-controlled colour vision test.

A dysfunction of dopaminergic retinal neurons is thought to occur in Parkinson's disease, manifesting itself in impaired performance on various visual discrimination tasks. We have investigated whether differences in colour discrimination could readily be detected between a normal group and a Parkinsonian group, using a computer-controlled test of colour vision. Although some individual Parkinsonian patients showed an abnormal elevation of colour discrimination thresholds, there was no significant difference between the normal group and the Parkinsonian group.

Age Factors↗

Visual thresholds measured with red test object on backgrounds of high and low luminance.

Visual thresholds measured at the central and midperipheral visual field have been tested in the eyes of a series of 10 healthy normal persons using a monochromatic red test light object (Goldmann area III, 25' of arc in the visual field) of 632 nm wavelength presented on white backgrounds of 150 cd/m2 (5000 K) and 1 cd/m2 (2800 K) luminance, as well as with no background illumination following a 45 min period of dark-adaptation. Another series of 10 normal subjects were tested with an equally large white (2800 K) test object shown on a white background of 1 cd/m2 (2800 K) luminance. Results obtained in congenital and acquired achromatopsia as well as in three relatively mild cases of rod-cone dystrophy have been related to the normal thresholds.

Adult↗

Oral contraceptive use, caffeine consumption, field-dependence, and the discrimination of colors.

We attempted to validate laboratory research which indicated that single doses of oral contraceptives (OCs) and caffeine affect the ability to discriminate colors (Böhme & Böhme, 1985). We did this in a nonlaboratory setting by surveying habitual use of OCs and caffeine by 43 female college students and relating that information to their performance on the Farnsworth-Munsell 100-Hue Test. When field-dependence, conceptualized as an indirect measure of sensitivity of the nervous system and previously shown to be strongly related to color discrimination, was included in the analyses, the results supported Böhme and Böhme's findings. For Trays 2 and 3 of the 100-Hue Test (yellow through blue of the color spectrum), higher caffeine consumption among OC users was related to poorer color discrimination, whereas, among nonusers of OCs, it was related to better performance. Study design limitations do not permit attribution of causation to either caffeine or OCs at this time.

Adolescent↗

Minimalist surface-colour matching.

Some theories of surface-colour perception assume that observers estimate the illuminant on a scene so that its effects can be discounted. A critical test of this interpretation of colour constancy is whether surface-colour matching is worse when the number of surfaces in a scene is so small that any illuminant estimate is unreliable. In the experiment reported here, observers made asymmetric colour matches between pairs of simultaneously presented Mondrian-like patterns under different daylights. The patterns had either 49 surfaces or a minimal 2 surfaces. No significant effect of number was found, suggesting that illuminant estimates are unnecessary for surface-colour matching.

Adult↗

Age covariance between 100-Hue color scores and quantitative perimetry in primary open angle glaucoma.

Color vision tests have shown promise as an early indicator of optic nerve compromise in primary open angle glaucoma (POAG). In this context, it is of interest to know how well color test performance correlates with an accepted measure of glaucomatous optic nerve damage, such as is provided by quantitative static perimetry. We found correlation values for 96 glaucoma suspects (ocular hypertensive patients) and 110 patients with POAG. No significant correlation values were found for the suspect group when age correction was applied to the color variable. Similarly, for the patients with POAG, age correction of the color test scores reduced all age group correlation values below significance, except for the age group 60 to 69 years. These findings conflict with another recent study reporting significant correlation between Farnsworth-Munsell 100-hue color test scores and visual field performance for glaucoma suspects but which did not correct for age. We interpreted our results for the glaucoma suspects and patients with glaucoma to indicate some independence of mechanisms responsible for early color loss compared with visual field loss.

Adult↗

[Clinical value of the colored contrast sensitivity test. Preliminary note].

Evaluation of color contrast sensitivity is a new test for the assessment of visual capacity and especially of light stimulation transfer along the optic pathway. The color technique yields more accurate results. It is combined with previously existing functional examinations and allows very early detection of subclinical signs of starting pathological processes.

Color Perception Tests↗

Testing visual capabilities for medical surveillance or to ensure job fitness.

A rationale is presented for designing screening-type eye examinations to document visual capabilities for specific jobs or changes in visual function following exposure to specific ocular hazards. Possible applications to clinical situations are also discussed. A battery of tests that includes contrast (glare) sensitivity, distortions in macular imaging, and color vision is detailed for use with three populations: automobile driver's license applicants, visual display operators, and laser users, including military as well as nonmilitary installers and repairers of optical fibers for communications.

Automobile Driving↗

[The color vision in patients with optic neuritis and chronic open-angle glaucoma].

Twenty eight cases (50 eyes) of chronic open-angle glaucoma and 21 cases (27 eyes) of optic neuritis were investigated with FM 100-hue test and panel D-15 test. In patients with optic neuritis, 70.37% and 85.19% of the affected eyes appeared abnormal in Panel D-15 test and FM 100-hue test respectively. The main defects were tritan-like in both of the tests. In patients with chronic open-angle glaucoma, 20% and 32% of the affected eyes had abnormal results in Panel D-15 test and FM 100-hue test respectively. The main defects were also tritan-like color vision defect. The total error scores of FM 100-hue test in patients with chronic open-angle glaucoma had no relation with the cup disc ratio and the area of peripheral visual field but had relation with the area of central visual field.

Adolescent↗

Colour vision testing as an aid to diagnosis and management of age related maculopathy.

AIM: To provide a simple test that detects the onset of age related maculopathy (ARM), and can be used to monitor its severity. METHODS: Colour contrast sensitivity was measured using computer graphics techniques. Colour thresholds were measured along tritan and protan colour confusion axes in the presence of dynamic luminance noise. Thresholds were determined separately for two sizes of optotypes (6.5 degrees and 1.5 degrees). Natural pupils were used. Normal values for the test have been established. RESULTS: In all patients with unilateral age related macular degeneration, the smaller optotype was invisible in that eye and in almost all, the larger optotype could not be seen. In the symptomless fellow eyes (with ARM) the larger optotype thresholds were raised. The degree of loss was larger for tritan. For the smaller optotype, protan thresholds were elevated in the majority of patients. Tritan losses were greater and disproportionate to the loss seen with the larger optotype. Every person including those with minimal fundal changes had tritan test results for 1.5 degree optotypes >2 SD above the normal mean. Tritan thresholds varied with the severity of the ARM. CONCLUSIONS: The test is sensitive, simple and quick to administer, and easy for patients. Therefore, it should be useful in detecting and monitoring elderly people with age related changes in their fundi before irreversible loss of vision has occurred.

Aged↗

Study of estimation of color recognition on the dentist. On the ability of subjects to discriminate color in terms of hue, value and chroma.

The tooth crown color space model was manufactured and the improvement of the color representation and communication on the dental clinic have been trying. The study of color discrimination by dentist and student viewing with the use of tooth crown color chips reported here in basic knowledge on the color sensitivity of human eye. The test card were 55 x 90 mm in size and the color chip, 5 x 10 mm. The paired color chips were placed on the test card to have a 2 mm distance between them. Color difference of two tooth crown color chips on the test cards was 3.5 (delta E*ab), the combination of hue, value and chroma was constant of all cards. The subjects were 22 people, 6 dentists and 16 dental school students with normal color sensibility. In proportion of method of comparison for surface color (JIS Z 8723), the subject observed the test card which were different of hue, value and chroma on the their naked-eye, were investigated to evaluate their judgement of the test cards. The following results were obtained. The standard of judgment for the color discrimination was made firstly in terms of hue, secondly in terms of value, and thirdly in terms of chroma.

Adult↗

[Evaluation of the desaturated Panel D-15. I. Method of quantification and normal scores].

Description of a method of quantification of the desatured Panel D-15 test: the principle was the calculation of the differences between the caps of the desatured Panel D-15, according to the differences between the corresponding caps of the 100-hue test, thus allowing the calculation of partial and total scores. 337 normal subjects, divided in 5 years age groups, were examined by this procedure. A color discrimination impairment was evidenced, the total scores being increased in the older age groups. These results give norms for clinical evaluations.

Adolescent↗