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Validation of the Holmes - Wright lanterns for testing colour vision.

The recently introduced Holmes - Wright Type A and Type B lanterns and the Farnsworth lantern were administered to 100 observers with normal colour vision and 100 observers with defective colour vision. With the fail criteria adopted, all normals passed the Holmes - Wright Type A lantern and with one exception all normals passed the Farnsworth lantern. However, 8% of normals failed the more difficult Holmes - Wright Type B lantern. It is noted that the normals who fail this lantern test appear to do so not because of poor colour discrimination but because the coloured stimuli presented by the lantern have a point brilliance close to the average chromatic threshold. About one-third of the colour vision defective group passed the Farnsworth lantern and between 14 and 17% passed the Holmes - Wright Type A lantern depending on the test procedure used. Only two mild deuteranomals in the sample of 100 colour abnormal observers succeeded in passing the Holmes - Wright Type B lantern. Dichromats and severe anomalous trichromats fail all three lanterns so that those who pass are all mild anomalous trichromats. A significant proportion of protanomals pass the Farnsworth lantern and some protanomals pass the Holmes - Wright Type A lantern despite their reduced sensitivity to red light and correspondingly reduced signal range for red signals.

Color Perception Tests

Clinical experience with the Lovibond Colour Vision Analyser. Results from the examination of normal and congenital colour-deficient subjects.

The Colour Vision Analyser was used for testing 98 persons of both sexes, aged from 10 to 70 years, and recognized as normal by means of pseudo-isochromatic plates and an anomaloscope. A drop of the saturation thresholds from yellow to green and from blue to purple was observed from the age of 40 years. The saturation thresholds from yellow to green was found lower in every age group than that from blue to purple. Congenital colour defects could be completely distinguished from normal subjects. As for the classification in types, those diagnosed as deutan by means of the anomaloscope were also diagnosed as deutan by the Analyser, however, there were, among those diagnosed as protan by the anomaloscope, some subjects who were diagnosed as deutan by the Analyser. Nearly all cases could be classified as anopia or anomaly.

Adolescent

Pattern of dysfunction in progressive cone dystrophies--an extended classification.

An extended classification for progressive cone dystrophies is proposed on the basis of the retrospective analysis of the clinical and electrophysiological findings obtained in a series of 91 patients with progressive cone dystrophies and of a review of the literature. This classification depends on the different patterns of electroretinographic responses. Four main categories and ten subgroups are distinguished. Generalized cone dystrophies are most frequent (76/91), affect all types of cones, and may be subdivided according to the degree of rod involvement. In selective cone dystrophies (8/91), the three cone types are affected differently as detected with the color electroretinogram. They are subdivided on the basis of the cone type predominantly involved. Additional inner retinal transmission defects may occur in cone dystrophies (3/91). They are identified by an alteration in the b/a-wave ratio on the electroretinogram and may affect the cone or rod pathway. Localized cone dystrophies (4/91) are limited to certain retinal areas.

Adolescent

Colorimetry by a new principle.

A simple and informative method is described for determining the type and extent of color defects. The subjects' responses are registered automatically on a chromaticity diagram that is based on the newtonian model. Color defects are readily identifiable by a skewing of the normal central gray area toward the defectively perceived color. The examination permits independent variation of hue and saturation for each color and requires less than five minutes for the entire procedure. Unlike conventional color tests, the present method indicates exactly what colors are or are not seen at any level of saturation.

Adolescent

Impaired color discrimination among viscose rayon workers exposed to carbon disulfide.

A possible effect of chronic carbon disulfide exposure on the optic nerve was studied by giving the Farnsworth Munsell 100-Hue Test for color discrimination to 62 exposed and 40 nonexposed men. Carbon disulfide exposure did not relate to specific pattern defects in color discrimination, but impaired color discrimination occurred significantly more often in the exposed group than among the referents. The abnormal findings suggest an impairment in the receptiveness of the ganglion cells or demyelination of the optic nerve fibers.

Adult

Peripheral cone contrast sensitivity in glaucoma.

Colour vision tests for detection of glaucomatous damage frequently suffer from two problems: most tests are confined to foveal vision, whereas defects tend to appear first extrafoveally; and the modulation directions in colour space are not optimal. This paper deals with peripheral testing à la Yu, Falcao-Reis, Spileers and Arden [(1991) Investigative Ophthalmology and Visual Science, 32, 2779-2789], and investigates whether there are modulation directions that show preferential sensitivity reduction in glaucoma. In 14 eyes with early glaucoma, 17 risk eyes and 10 normals, 12 deg peripheral colour contrast thresholds were determined for L, M, S, L-M and L+M test directions. Threshold elevations were correlated in all test directions, with S modulation yielding the largest elevations.

Aged

Colour vision screening in glaucoma: the Tritan Album and other simple tests.

Results from simple colour vision tests used for the detection of the Type III colour vision deficiency in glaucoma and ocular hypertension are presented. We assessed 49 patients with primary open angle glaucoma, 16 ocular hypertensives, 54 age matched normals and 50 young normal observers using six established tests and the recently introduced Tritan Album. This test was introduced specifically for acquired colour vision deficiencies. Results show in general that individual tests have low sensitivity and poor screening efficiency. The best screening efficiency was achieved by the City University Colour Vision Test and the AO HRR plate test, no acquired tritan defects were identified by the Farnsworth F2 plate, and the Tritan Album had very low sensitivity (the lowest excluding the F2 plate). Best results were obtained from a combination of City University and HRR test scores and this combination could provide useful additional data on colour vision in a glaucoma screening programme.

Aged

Red-green mixture thresholds in congenital and acquired color defects.

A color television display was used to measure thresholds for mixtures of red and green on a white background; red and green components could be either incremental, decremental or zero. Ellipses are fitted to a plot of green contrast as a function of red contrast, and it is argued that the length of the ellipse is a measure of red-green color discrimination and the width of the ellipse is a measure of luminance discrimination. It is shown that the technique reliably distinguishes normals from congenital color defectives and also protan from deutan subjects. For some cases of acquired color defects (e.g. optic neuritis), there is a roughly equal loss of color and luminance discrimination whereas, in other cases (e.g., hereditary optic atrophies), the loss of color discrimination is much greater than the loss of luminance discrimination.

Adult

Visual evoked response in syphilitic optic atrophy. A case report.

A case of neurosyphilis is described. The presenting symptoms were reduced visual acuity and impaired colour vision. The examination revealed bilateral optic atrophy and acquired red-green colour defect. A syphilitic aetiology was based on positive serological tests in blood and CSF, pleocytosis and increased total protein in the CSF. The abrupt decline in visual acuity was arrested by treatment with penicillin and systemic steroids, but normalization of vision was not obtained. All VER-records, of P2 latencies and morphologies were surprisingly normal, but the amplitudes were reduced.

Color Vision Defects

Pathologic scotopization: a shortened Nagel-II anomaloscopic micro-screw method.

The Nagel-II micro-screw method uses eleven colour equations between 620 and 560 nm. The luminance settings are given and are based on the data of colour normal individuals. In the shortened version, intended to detect pathologic scotopization, it is ascertained at which position of the micro-screw the patient's colour adjustments drop beneath the level of 60 scale Units. A total of 64 patients was examined. 29 congenital colour defectives and 35 acquired colour defectives. With the shortened micro-screw method the patients can be divided into four groups: (1) a group without pathologic scotopization, which includes congenital protan defectives: (2) a group in which pathologic scotopization starts; (3) a group with evident pathologic scotopization, due to Stargardt's disease and other cone dystrophies; and (4) a group with complete pathologic scotopization, which includes the congenital achromats and the end-stages of the cone dystrophies.

Color Perception Tests

Visual thresholds in the deutan type of red-green deficient colour vision.

Defective temporal integration for a foveally fixated 100' of arc red (660 nm) Btest flash presented on a 30 cd/m2 yellow ( Schott , OG 530) background was measured in subjects with deuteranopia , as well as in subjects with anomalous trichromacy of the deutan type. The mean integration time was 77 +/- 17 ms in 12 normal subjects but only 35 +/- 6, 46 +/- 11 Band 41 +/- 15 ms in respectively 6 subjects with deuteranopia , 7 with extreme deuteranomaly Band 9 with deuteranomaly . An increase in the test duration from 10 to 200 ms increased the mean relative sensitivity by 0.85 +/- 13 log units in the normal subjects compared with 0.45 +/- 0.05, 0.57 +/- 12 and 0.56 +/- 19 in subjects with deuteranopia , extreme deuteranomaly and deuteranomaly .

Adolescent

[Juvenile neuronal ceroid lipofuscinosis (Spielmeyer-Vogt disease)].

BACKGROUND: The neuronal ceroid-lipofuscinosis (NCL) belongs to progressive neurodegenerative disorders of childhood with both ophthalmologic and neurologic symptoms. In the most common type in Germany, the juvenile type, the ophthalmological examination is essential for an early diagnosis. PATIENT: A 5-year-old boy had exhibited a loss of visual acuity, visual field and colour perception in his pre-school age. His clinical features and electrophysiologic data are presented. The final diagnostic clues were drawn from the neuropediatric and cytologic examinations. RESULTS: This patient shows the typical clinical feature of the juvenile NCL with a relatively rapid visual loss with bull's eye maculopathy in the pre-school- to early school age. His electroretinogram was abolished, and his EEG showed pathologic results. The diagnosis could be established by electron microscopy of his lymphocytes. Epilepsy and intellectual defects are expected to set in only few years later. CONCLUSIONS: Although there is no therapy, the ophthalmologist should be aware of this rare entity because prognostic counselling, social help and perhaps genetic counselling could be offered to the families. In many cases, a prenatal diagnosis is possible.

Child

Concurrent visual conversion reaction and simulated colour vision defects in a 12-year-old child.

Visual conversion reaction (VCR) is a psychosomatic anomaly which occasionally manifests in children, most commonly in the form of reduced vision and visual field defects. Malingering or conscious simulation for secondary gain would appear to be rare in children but occasionally VCR and simulation coexist. A case history is presented of a 12-year-old child with behavioural and reading difficulties who manifested reduced vision most probably attributable to VCR and severe colour deficiency, which was best explained in terms of simulation or malingering.

Child

Impaired colour discrimination among workers exposed to styrene: relevance of a urinary metabolite.

OBJECTIVES: To survey the loss of colour vision among Japanese workers who have been exposed to styrene concentrations currently considered low (about 20 ppm). Also to assess the effects of styrene by examination of the nature of the relation between disorder of colour vision and age, alcohol consumption, and other variables. METHODS: Colour discrimination was examined in 64 male workers exposed to styrene (mean age; 38.0, mean exposed years; 7.0) and in 69 controls (mean age; 38.0). A standardised questionnaire was adopted to collect work history, occupational or non-occupational solvent exposure, alcohol consumption, and drug use. Colour vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the colour confusion index (CCI). RESULTS: The mean atmospheric styrene concentration was about 20 ppm. The mean urinary concentration of mandelic acid was 0.22 g/l. There was a significant difference in CCI between exposed workers and age matched controls. Colour vision of workers whose concentration of urinary mandelic acid was > or = 0.42 g/l was significantly impaired when compared with workers whose concentration was < 0.42 g/l. Multiple linear regression analysis that controlled confounding variables such as age, alcohol consumption, smoking, and educational attainment showed that the CCI was significantly related to the concentration of urinary mandelic acid. In both exposed workers and controls, the types of defects were mostly blue-yellow loss, although a few subjects showed complex loss. No one showed only red-green loss. CONCLUSIONS: These findings suggest that exposure to moderate styrene concentrations can lead to impairment of colour vision, and that there is a significant correlation with the urinary metabolite of styrene.

Adult

Defective colour vision can impede information acquisition from redundantly colour-coded video displays.

Earlier findings showed that redundant colour coding decreased response times and reduced errors in carrying out various tasks that required information acquisition from the video display of an electronic flight instrument system. The results of this experiment showed that observers with defective colour vision have slower response times and higher error rates than normal observers for some of the tasks and that their performance is similar to that of colour-normal observers for a monochrome display. However, they were not disadvantaged when blue was used to colour code the target feature. Protanopes were shown to be especially disadvantaged in responding to a red 'fail' message.

Adult

A comparative study of Hardy-Rand-Rittler and Ishihara colour plates for the diagnosis of nonglaucomatous optic neuropathy.

OBJECTIVE: To determine the ability of the Hardy-Rand-Rittler (HRR) and Ishihara colour plates to detect acquired colour vision defects in patients with nonglaucomatous optic neuropathy (NGON). DESIGN: Prospective study. SETTING: Neuro-Ophthalmology Unit of the Wilmer Eye Institute, Baltimore. PATIENTS: A total of 178 consecutive patients (349 eyes) referred to the Neuro-Ophthalmology Unit and the General Eye Service of the Wilmer Eye Institute and examined by two of the authors were enrolled from July 1992 to June 1993. OUTCOME MEASURES: Results of testing with HRR and Ishihara plates. RESULTS: Among the 202 eyes that were found to have no ocular disease on neuro-ophthalmologic testing, the HRR plates gave a normal result in 168 (83.2%), compared with 196 (97.0%) with the Ishihara plates (p < 0.0001). The HRR plates detected an acquired colour vision deficit in 48 (87.3%) of the 55 eyes with NGON, compared with 38 (69.1%) for Ishihara plates (p = 0.001). The values for the eyes with NGON with a visual acuity of 20/25 or better were 76.5% (13/17) and 35.3% (6/17) respectively (p = 0.008) and with a visual acuity less than 20/25, 92.1% (35/38) and 84.2% (32/38) respectively. CONCLUSIONS: For patients with unilateral or bilateral NGON, HRR plates are more likely than Ishihara plates to detect a colour vision defect, particularly when the visual acuity is 20/25 or better. However, neither test is sensitive enough to be used as the sole criterion for the diagnosis of NGON. The results of comparison of colour perception of the two eyes may be more useful than absolute colour vision responses, particularly in patients with unilateral disease.

Adolescent

Clinical analysis of colour vision deficiencies with The City University test.

The City University colour vision test (CUCVT) was used for the examination of 158 subjects suffering from congenital colour vision defects (36 protanopes, 122 deutanopes) and its results were compared with that of an anomaloscope and of the panel D-15. 23% of the subjects classified as protanopes and 98% of the subjects classified as deuteranopes by means of the anomaloscope were also classified as such by means of the CUCVT, while 93% of the subjects classified as protanomalous and 90% of the subjects classified as deuteranomalous by means of the anomaloscope gave normal answers at the CUCVT. The results of the CUCVT were almost the same as with panel D-15 except protanopia. The colour spots of each plate of the CUCVT were plotted on a CIE chromaticity diagram and the results of this study are also reported.

Adolescent

The influence of homonymous visual field disorders on colour sorting performance in the FM 100-hue test.

An influence of visual field disorders on sorting performance in the FM 100-hue test is reported. Patients with left-sided field disorders performed worse in the conventional testing direction, i.e. from left to right, compared with patients with right-sided defects. Reversing the direction of sorting led, however, to a similar impairment in patients with right-sided field defects. Observations in normals tested under different conditions of hue sorting support the view that the difference obtained cannot be accounted for by a hemisphere difference in colour processing but by the strategy adopted by subjects.

Adolescent