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Repeatability of the C-100 colour vision test.

BACKGROUND: The C-100 colour vision test has been shown to have a high validity for diagnosing the type of red-green colour vision defect, however, there is little information on the repeatability of the test. This study examines the repeatability of the C-100 in classifying the colour vision defect as either protan or deutan. METHODS: The C-100 was administered on two occasions to 58 subjects with congenital red-green colour vision defects. The sessions were separated by a minimum period of 10 days. RESULTS: The repeatability of the C-100 was high with a kappa coefficient of agreement for diagnosis of 0.96. The few discrepancies were misclassifying protans as deutans. CONCLUSION: The C-100 is a highly repeatable test in terms of separating protans from deutans. However, if a discrepancy occurs, it is more likely to be a protan misclassified as a deutan rather than vice versa.

Adult↗

[Color vision test for detection and evaluation of dyschromatopsia].

METHODS: The color vision test for diagnosis and evaluation of the dyschromatopsias consists of a set of 92 colored test charts of the pseudochromatic type, a lamp and a test report giving a graphic image of the sensitivity to color deficiency. RESULTS: The test makes it possible to identify each neutral zone of all types of dyschromatopsia, places the neutral zone within the color spectrum and establishes its extent according to 6 axes (Protan, Deutan, Tritan, Tetartan, Scotopic and Monochromatic) and 10 levels. The visual sensitivity to color is measured on a 10 point scale, just as visual acuity is. Between a normal sensitivity to color, which is marked 1, and an anopia (i.e complete lack of visual sensitivity to color along one axis), marked 0, there are 9 intermediary levels marked 0.9; 0.8: 0.7; 0.6: 0.5; 0.4; 0.3; 0.2 and 0.1. CONCLUSION: Testing is important for all kinds of eye diseases or common diseases which affect eyesight making possible not only early diagnosis of a disease but also treatment follow-up.

Color Perception Tests↗

Evaluation of a chromatometer: a new method for blue-yellow or green-red visual comparisons, and anomaly screening techniques.

BACKGROUND: Malbrel's chromatometer is a new apparatus which allows color vision to be monitored. The aim of this study was to assess the accuracy of this new examination method. MATERIAL/METHODS: The color vision of a patient was analyzed using a chromatometer for direct heterochromatic visual comparisons. The patient's task was to adjust, using one eye only, the brightness of a yellow (or red) window to the one of a fixed blue (or green) window. Overall, 158 patients, aged 20 to 28, took part in the experiment. First, parametric means were used to study the response distributions and the luminous effects on the responses. Second, using non-parametric means, we considered that a patient had an anomalous color vision according to the chromatometer if the response was higher than the 95th percentile or lower than 5th percentile. Third, anomalous responses were compared with the Ishihara plates and Farnsworth 28-hue responses. RESULTS: The effect of a luminous stimulus on the response was significant (adjusted to the patient effect). Thus, the chromatometer appears to be a good method to analyze color vision. This apparatus was easy to use and constituted a sensitive and specific test with high negative predictive value. CONCLUSIONS: The chromatometer can be used as a first-line screening test to detect color vision anomalies during ophthalmology consultations. The chromatometer can be useful in identifying early ocular disease, monitoring disease development, or checking possible iatrogenic effects of a specific treatment.

Adult↗

Testability of a color vision screening test in a population with mental retardation.

PURPOSE: The purpose of this study was to determine the testability of the "Co or Vision Testing Made Easy" color vision test, marketed as a screening test for young children, in a population of individuals with mental retardation. The test uses simple geometric figures that are easily identified. Previously, the test has demonstrated validity as a measure of color deficiency. METHODS: The test was presented to Special Olympic athletes, who are individuals with mental retardation or significant developmental delay, at four sites: the 1997 World Winter Games in Toronto, Canada; the Texas Summer Games in Houston, Texas; the Massachusetts Summer Games in Boston, Massachusetts; and Regional European Swim Competition in Seville, Spain. The criteria for passing was 8 correct responses on the first trial or 9 of 9 on the second attempt. RESULTS: Testability in Toronto, Canada; Houston, Texas; and Seville, Spain was high--95.5%, 98.7%, and 95.7%, respectively. Testability, however, dropped to 78.8% during the Boston, Massachusetts screening. There was no apparent difference in the testing environment that would account for the difference. The overall rate of testability was 93.2% for the 1078 athletes screened. The frequency of males identified as color deficient was similar to that expected in the general population; only two females (in Spain) failed the color vision screening. CONCLUSIONS: The "Color Vision Testing Made Easy" color vision test was successfully completed by a very high percentage of Special Olympics athletes. These results suggest that this test is useful in screening this population for color deficiencies, and that the prevalence of color vision deficiencies is approximately the same in individuals with mental retardation as in the general population.

Adolescent↗

[Computer-assisted testing of the sense of color].

The authors used the discrimination method--pseudoisochromatic phases and the comparison-assortment method for the chromatic sense examination in a group of subjects working in the motor transport and chemical textile dying. Computer programs were devised for examination data processing and for diagnosis display. After each testing, the data of each subject are added to the patient's card to be subsequently looked up and used for statistics.

Automobile Driving↗

Dichromatic color language: "reds" and "greens" don't look alike but their colors do.

When protanopes or deuteranopes arrange the Farnsworth Dichotomous Test colors in order of similarity, they reveal their lack of red/green hue discriminations by alternating chips that the normal trichromat sees as reddish and greenish test colors. The dichromatic orderings follow a systematic variation in saturation of blue hues through neutral and into yellow hues as described by theory for each of the two types. Some dichromats who show the typical test behavior nevertheless use reddish and greenish hue terms appropriately when instructed to name the same test colors. Lightness cues are probably used by these dichromats in the naming task but ignored in the perceptual similarity task. Thus, unlike normal trichromats, who use similar names for perceptually similar colors, dichromats may use dissimilar names for perceptually similar colors. In this way they can achieve concordance with the normative language system despite its discordance with their impoverished color perceptions.

Color Perception↗

Clinical results of the blue-light filtering AcrySof Natural foldable acrylic intraocular lens.

PURPOSE: To verify the safety and effectiveness of the new AcrySof Natural (Alcon Laboratories, Inc.) blue-light filtering intraocular lens (IOL), which was designed to achieve a light-transmission spectrum similar to that of the natural human crystalline lens. SETTING: Multicenter U.S. clinical trial. METHODS: In a prospective randomized patient-masked multicenter study, 150 patients received the AcrySof Natural IOL and 147 patients received the AcrySof single-piece IOL as a control. Patients with bilateral age-related cataracts who were willing and able to wait at least 30 days between cataract procedures and had verified normal preoperative color vision were eligible for the study. Standardized surgery included a 4.0 to 5.0 mm capsulorhexis and phacoemulsification. All lenses were inserted in the capsular bag, with verification of in-the-bag placement of both haptics. In all bilateral implantation cases, the same model IOL was used in each eye. Postoperatively, contrast sensitivity and color perception were measured up to 180 days and up to 1 year (for visual acuity) after implantation. RESULTS: No statistically significant differences were discovered between the 2 patient groups in visual acuity, contrast sensitivity evaluated under mesopic and photopic conditions, or the number of patients who passed the Farnsworth D-15 color perception test. There were no lens-related adverse events in either group. CONCLUSIONS: The blue-light filtering AcrySof Natural IOL was equivalent to the conventional AcrySof lens in terms of postoperative visual performance. Additional long-term clinical studies should show whether the IOL actually provides the theoretical benefits to retinal health.

Acrylic Resins↗

[The role of color vision disturbances in diagnostics of early diabetic retinopathy].

PURPOSE: The evaluations of color vision sensitivity in children with type I diabetes mellitus without retinopathy. MATERIAL AND METHOD: We examined 96 young patients. They was divided into three groups: I: 35 children from 7 to 16 years old with insulin-dependent diabetes mellitus duration of 1-8 years, II: 30 children with type I diabetes lasting more then 8 years, III--31 non-diabetic subjects as a control-matched for age and sex, without visual or systemic symptoms. The examinations of colour vision sensitivity were done with the IF-2AII-color Anomaloscope. In all cases were tested the dynamic blue-green equation of Moreland and two variables were determined: setting (matching) range (SR), calculated mid point (matching mid point) (CMP). RESULTS: In the blue-green equation setting range (SR) was significantly (p < 0.01) enlarged in the II group (diabetes mellitus duration > 8 years) and calculated mid point (CMP) was shifted but no significant. The results indicate a diminution of the colour discriminating sensitivity in the short wavelength half of the visible spectrum and diminution of the blue cone sensitivity in early diabetic retinopathy. CONCLUSIONS: Blue-green colour vision testing with the anomaloscope may serve as an additional test in the diagnosis of early diabetic retinopathy in children without vascular changes at the eye fundus.

Adolescent↗

Computerized colour vision testing.

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.

Adult↗

Performance of air traffic control tasks by protanopic color defectives.

Air traffic controllers perform a number of tasks which involve color identification, color discrimination, and color naming. Normal color vision is required for air traffic controllers, although the requirement is currently under review. The most critical task involving color is the distinction of red and black on flight strips; the distinction must be made reliably, quickly, and routinely for flight safety. In this study of four protanopes and three normals, all the protanopes were unable to make this distinction reliably under the lighting levels encountered at air traffic control (ATC) centers, whereas none of the normals had any difficulty. Protanopes also made numerous errors with other ATC tasks involving color. The use of a red filter, often recommended to aid color defectives, actually made performance worse and additionally compounded the usual protanopic loss of brightness for red light. When Snellen visual acuity was tested using the red filters, protanopes needed up to four times larger letters than the color normals. It is concluded that protanopes have inadequate vision for safe performance of some current ATC tasks.

Aviation↗

Impairment of color vision among workers exposed to low concentrations of styrene.

A field study was conducted among 21 male workers exposed to styrene of concentration below 30 ppm in a fiber-reinforced plastic boat manufacturing plant. Twenty-one male workers with similar age groupings, years of education, and social and occupational state served as referents. The mean end-of-shift urinary mandelic acid (MA) and phenylglycoxylic acid (PGA) for the exposed workers were 84 mg/g creatinine and 66 mg/g creatinine, respectively. The Lanthony D-15 Hue Desaturated Panel was used to evaluate color discrimination of the exposed and referent groups. The results of the test were expressed as total color difference score (TCDS). The exposed workers' mean TCDS (a higher score denotes poorer color discrimination ability) was significantly (p < 0.0006) higher than the referents'. Neurobehavioral tests were also conducted, using the World Health Organization's Neurobehavioral Core Test Battery (NCTB). All the results of the NCTB were poorer for the exposed than for the referents. However, significant differences were observed only for Digit Span, Digit Symbol, and Benton Visual Retention tests. These results suggest that low exposure to styrene could affect some psychometric performance and may impair color vision.

Adult↗

Keratoconus associated with cone-rod dystrophy: a case report.

A 31-year-old man with bilateral keratoconus associated with apical corneal scarring underwent uneventful penetrating keratoplasty in his left eye. Postoperatively his best-corrected visual acuity did not improve beyond 20/120. Examination of the fundus revealed features suggestive of bull's eye maculopathy. On performing an electroretinogram study of both eyes, grossly delayed implicit time with reduced amplitudes of the rod response and extinguished cone waveforms were noted, indicating cone-rod dystrophy. Color blindness was also noted on testing with Ishihara's pseudoisochromatic plates. Genetic counseling showed this to be an isolated defect with negative family history. Preoperative electrophysiologic studies may have a prognostic role in these cases.

Adult↗

Comparison of colour discrimination and electroretinography in evaluation of visual pathway dysfunction in aretinopathic IDDM patients.

The slow progression of diabetic retinopathy makes it difficult to assess the effects of intervention therapy. There is thus a need for surrogate markers of visual change in diabetes. Colour vision tests and electroretinography (ERG) may be useful in this regard; yet little is known of their relative performance in the assessment of visual dysfunction in diabetes. The aim of the present study was to compare colour discrimination (100 hue test) and ERG indices (oscillatory potentials (OP) and pattern ERG (PERG)) in the evaluation of aretinopathic IDDM patients. Colour discrimination was abnormal in 10 aretinopathic IDDM patients when compared with nine age matched controls; mean square root 100 hue error scores were 10.38 (SD 2.89) versus 4.77 (1.87) respectively, p < 0.01. OP implicit times of the ERG were also abnormal; for example, for right eye, mean OP1 implicit time for diabetics versus OP1 implicit time for controls was 20.1 (2.0) versus 18.6 (1.4) ms, p = 0.03. Comparison of the two techniques suggested that the 100 hue test was more sensitive and more specific than ERG OP implicit times in the detection of diabetic visual dysfunction in these patients.

Adult↗

Comparison of the standard pseudoisochromatic plates--Parts 1 and 2--As screening tests for congenital red-green color vision deficiencies.

BACKGROUND: The Standard Pseudoisochromatic Plates-Part 2 (SPP-2) are designed primarily as a screening test for acquired color vision deficiencies. However, results from several studies suggest that the SPP-2 may also be effective as a screening test for congenital red-green color vision defects. METHODS: In this study, the screening effectiveness of the SPP-2 was compared with the Standard Pseudoisochromatic Plates-Part 1 (SPP-1) to determine whether clinicians must use both tests: the SPP-1 to screen for congenital color vision defects and the SPP-2 to screen for acquired color vision defects. RESULTS: The results showed that, when using the recommended scoring criterion for the SPP-1, the SPP-2 test is slightly more sensitive in detecting congenital red-green defects. CONCLUSIONS: Clinicians can use the SPP-2 to screen for both congenital and acquired color vision defects.

Adolescent↗

Introducing a new computer-based test for the clinical evaluation of color discrimination.

PURPOSE: To evaluate the Portal color sort test (PCST), a new computer-based test of color vision, by comparing it with a series of clinical tests of color vision in normal and color deficient subjects. DESIGN: Prospective clinical laboratory study. METHODS: Fifty-nine subjects with normal trichromatic vision or with congenital color vision defects underwent a series of color vision tests that included the 15-plate Ishihara test, the D-15 Farnsworth-Munsell test (D-15), the Farnsworth-Munsell 100-Hue test (FM 100-Hue), and the PCST under rigorous standardized conditions, as recommended by the respective manufacturers. The PCST generates a numerical discrimination score comparable to the FM 100-Hue. RESULTS: To test validity, discrimination scores generated by the PCST were compared with scores on the FM 100-Hue. The Spearman rank correlation between discrimination scores on the FM 100-Hue and the PCST was 0.8 (P < .001). Reliability was assessed by asking patients to retake the PCST at a later sitting. Patients retaking the PCST achieved similar scores on their second sitting as on the first. The correlation in the score between the two tests was 0.7 (95% confidence interval [CI]: 0.4-0.9, P < .001). Median (quartiles) time to complete the PCST was 3.1 minutes. This was faster than the FM 100-Hue time (P < .001), but slower than both the Ishihara and the D-15 (both P < .001). CONCLUSIONS: This study suggests that the PCST, a test of color vision deficiency, can be used effectively and reliably as a tool for screening (comparable to the Ishihara plates and the D-15) and grading (comparable to the FM 100-Hue) color discrimination ability.

Adolescent↗

Classification of Farnsworth-Munsell 100-hue test results in the early treatment diabetic retinopathy study.

PURPOSE: To classify and describe clinically meaningful classes of color vision defects using pretreatment Farnsworth-Munsell 100-hue results from the Early Treatment Diabetic Retinopathy Study (ETDRS) patients using standard statistical techniques. DESIGN: The ETDRS was a randomized trial investigating retinal photocoagulation and oral aspirin in diabetic retinopathy. METHODS: Farnsworth-Munsell (FM) 100-hue test was successfully administered before initiation of study treatment in each eye of 2701 of the 3711 ETDRS patients. Test results were converted into a Fourier series, classified by cluster analysis in the deferred-treatment group of eyes, and verified in the immediate-treatment group of eyes as separate samples. RESULTS: Cluster analysis uncovered thirteen distinct patterns. Pattern A (51% or 1366 of the eyes) showed unimpaired hue discrimination and was comprised of younger patients with no or little macular edema. Pattern B eyes (10% or 262) showed generalized impairment of hue discrimination with no main axis defect. Patterns C (C1, C2, C3), comprising 26% (or 698) of the eyes, showed increasing severity of the yellow-blue diabetic retinopathy defect, associated with increasing mean age and increasing macular edema severity. Patterns D (D1, D2), comprising 6% (or 164) of the eyes, were similar to the C patterns but showed a stronger yellow-blue defect. Patterns E (E1, E2, E3), or approximately 2% (or 38) of the eyes and predominantly male, exhibited the expected pattern for congenital protan defect. Patterns F, G, and H, approximately 6% (or 153) of the eyes, showed distinct patterns of one-sided axes. The nomenclature is arbitrary. CONCLUSIONS: Cluster analysis of FM 100-hue test results has found 13 patterns of impaired hue discrimination, helpful in understanding color vision defects in diabetes mellitus.

Adult↗

Visual fields: simplified screening and recording procedures.

In some cases, visual field screening must be greatly simplified in order to obtain clinically useful information. This becomes possible when specific techniques are used for anomalies such as relative central scotoma, hemianopsia, and glaucomatous field defects. A working knowledge of visual pathway anatomy and function enables the optometrist to efficiently screen for these disorders by confrontation with red test objects, with pseudoisochromatic plates, and with the tangent screen. After the type of field defect has been determined by initial screening, recording its parameters with the tangent screen follows easily.

Color Perception Tests↗