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[Clinical aspects of hypophyseal diseases from the viewpoint of the ophthalmologist].

The anatomy of the chiasmal region and the visual symptoms due to pituitary tumors will be presented from the viewpoint of an ophthalmologist. The importance of perimetry in every patient with otherwise unexplained loss of vision is stressed. Other tests (swinging flash light test, colour vision, screening ophthalmoscopy) are mentioned as well. An ophthalmologist should participate in the diagnosis as well as in the follow-up after treatment of any case with pituitary tumors.

Humans↗

The design of diagnostic tests for defective colour vision.

Pseudoisochromatic plates are among the most popular tests for defective colour vision. They are particularly good for screening but are less good in assessing the degree and type of the colour vision defect. To select colours for use in diagnostic plates a large number of colour defective subjects have made colour matches with the Lovibond Tintometer and the isochromatic data collected. Pseudoisochromatic plates have been printed using pairs of colours only and incorporating both a random dot and a regular dot format. These plates have proved effective in a clinical trial. Not only must pairs of inks be carefully selected to lie upon appropriate isochromatic lines but the luminance contrast between the two colours must be kept within 5%. Failure to control luminance contrast is as much a source of error in currently available pseudoischromatic tests as the inappropriate use of colour.

Color Perception Tests↗

A simplified screening test for identifying people with low vision in developing countries.

Simple but effective tests have been produced for screening subjects with low vision in developing countries. These tests of distance and near vision, based on the E test, were evaluated and validated in trials with people aged 4-90 years, and have been field tested in the health, education and rehabilitation services in 32 developing countries. Their sensitivity and specificity as screening tools for low vision have been calculated; sensitivity of 85% and specificity of 96% for the distance vision test, and sensitivity of 100% and specificity of 84% for the near vision test. The content and format of the tests have been demonstrated to be appropriate for developing countries, and their effectiveness for screening for low vision has been confirmed.

Adolescent↗

A new test for screening color vision: concurrent validity and utility.

Recognizing the need for an effective test for screening color vision in young children, we have developed a new pseudoisochromatic (PIC) plate test which is useful for a wide variety of observers at different ages. The test consists of four plates and responses can be used to categorize color vision as normal or as either red-green or blue-yellow defective. Results of this validation study with adults, both color normal and red-green defective, show a high degree of correlation between the new test and the Nagel anomaloscope: there were no false positives and only a few false negatives, which occurred with mild deuteranomalous observers. The validity of the test compares favorably to the Ishihara, F-2, and the AO-HRR screening plates. Results with toddlers (3 to 6 years) indicate that the task demands of the test are well suited for testing young children. The percentage of color defectives identified in the toddler sample using the new test is closer to the adult prevalence than results obtained with the F-2 and AO-HRR screening plates, which gave dramatically higher failure rates. The new test is culture-free and can be administered rapidly to both verbal and nonverbal observers using pointing or preferential looking.

Adult↗

Prospective, randomized, placebo-controlled, double-blind testing of colour vision and electroretinogram at therapeutic and subtherapeutic digitoxin serum levels.

In a prospective, randomized, double-blind study with 10 healthy probands, changes in colour discrimination and in the pattern electroretinogram (P-ERG) and visually evoked cortical potentials (P-VECP) were monitored at therapeutic and subtherapeutic digitoxin serum levels. There was a slight increase in the total error score in the Farnsworth-Munsell 100-hue test at 0.1 mg digitoxin per day in comparison with the placebo. P-ERG and P-VECP did not show any significant changes.

Adult↗

Evaluation of ocular safety: tirapazamine plus cisplatin in patients with metastatic melanomas.

Ninety-six patients with metastatic melanoma treated with two consecutive tirapazamine-cisplatin combination chemotherapy regimens were followed for signs of therapy-related ocular toxicity. Baseline and follow-up data were obtained such that each patient acted as his own control. A battery of vision-related tests was performed. These included: best corrected visual acuity, color vision, retinal fundus examination and electro-oculograms (EOG). A brief health-related quality of vision test was administered at each follow-up visit to detect and evaluate self-perceived changes in visual status. In the first study, 48 patients received i.v. tirapazamine over 2 h at 260 mg/m2 (group 1) while in the second study 48 patients (group 2) received i.v. tirapazamine at 390 mg/m2. Visual system assessment was conducted at three timepoints: first at baseline, then at 6 weeks post-baseline, i.e. after two courses of chemotherapy and visit two upon discontinuation of therapy. There was no difference in visual acuity between group 1 and group 2 at baseline, follow-up 1 or at follow-up 2. Grouped data indicate that visual acuity was not affected by either dosage of chemotherapy. Group 1 at baseline found 15% below the normal EOG cutoff point, increasing to 23% at follow-up 1 and increasing at follow-up visit 2 to 33%. Group 2 demonstrated the same EOG findings, but the results were more magnified: baseline, 24%; follow-up 1, 44%; and follow-up 2, 44%. After eliminating those with abnormal color vision baselines, 21% (nine of 42) group 1 patients demonstrated abnormal color vision total error scores at follow-up 1 and 16.7% (four of 24) at follow-up 2. Few individuals showed changes in the higher dosage group. With the exception of one person in each dosage group, all changes were along the blue-yellow (tritan) axis, which is associated with acquired color defects. Of 96 patients examined, proven fundus changes were found in only four subjects. These fundus findings included retinal hemorrhages, retinal nerve fiber layer infarcts (cotton wool spots) and small retinal pigment epithelium detachments. There was no systematic statistical significant difference among the various measures of visual system outcome between groups or test times. Data from all tests for individual patients in both groups reveals a sporadic distribution of changes in visual system tests. If toxicity were pronounced, one would expect consistency in the findings and all or most of the assessment tests would be abnormal for a particular patient. However, patients who were abnormal on one measure of acuity were not necessarily abnormal on the other measures.

Adult↗

Contrast/color card procedure: a new test of young infants' color vision.

We have developed a new test which can rapidly evaluate basic color vision in individual infants. The test consists of a series of large cards constructed with Munsell Hues. It uses a modified preferential looking procedure (FPL) and, to control brightness cues, incorporates a two-phase systematic variation of luminance. First, we evaluate an infant's ability to discriminate 9.5 by 16 degrees achromatic patches of varying luminance from a 26 by 65 degrees achromatic background of midrange luminance. In the second phase the test patch is chromatic and its luminance, relative to the background, is varied over a range of about 1.0 log cd/m2. The number of relative luminances chosen for each infant depends upon his/her performance in phase 1. Seventy 2- and 3-month-olds were tested with 4 broad-band chromatic patches, a red (dominant lambda = 660 nm), a yellow (dominant lambda = 580 nm), a green (dominant lambda = 520 nm), and a blue (dominant lambda = 475 nm). Results showed that 3-month-olds had little difficulty making any of the chromatic-achromatic discriminations but many 2-month-olds appeared to fail to discriminate the yellow and green from the background at relative luminances close to an adult brightness match. Most importantly, the test shows promise as a relatively simple, time-efficient, and portable tool for the assessment of early color vision.

Color Perception Tests↗

Effect of visual impairment on neuropsychological test performance.

Three vision-dependent neuropsychological tests of visual processing--Benton's Facial Recognition (FR), Judgment of Line Orientation (JLO), and Visual Form Discrimination (VFD)--were administered to subjects on the same day as routine ophthalmic examination. Seventeen subjects had Jaeger near vision of J5 (analogous to 20/50) or worse resulting from refractive error, while 13 control subjects had normal near vision of J1. Neuropsychological test scores of these groups were compared with each other and also the published standardization group for each test. Low near-vision subjects' performances on FR and VFD were significantly poorer than both control group subjects and standardization group subjects, but performance on JLO was not significantly altered. These results demonstrate that visual impairment can result in unexpectedly low scores on certain tests of visual processing, which suggests that poor vision might also affect results of other neuropsychological tests that involve vision, such as tests of visual processing and tests which use vision as a vehicle to deliver test stimuli to the relevant portions of the cortex. We therefore strongly urge examiners to secure control over potential bias resulting from reduced vision by instituting routine near visual acuity testing of all subjects prior to or during neuropsychological assessment.

Aged↗

[Automatic devices for testing field of vision].

Prototypes of two automated devices for visual field research on the basis of a computer: visual field analyser (automated perimeter) and the device for detection of scotomas in the central visual field (automated campimeter)--are described.

Computers↗

Discrimination of wide-field images as a test of a peripheral-vision model.

In order to test a model of peripheral vision, various contrast sensitivity functions (CSF's) and fundamental eccentricity constants (FEC's) [see J. Opt. Soc. Am. A 8, 1762 (1991)] were applied to real-world, wide-field (6.4 degrees-32 degrees eccentricity) images. The FEC is used to model the change in contrast sensitivity as a function of retinal eccentricity. The processed test images were tested perceptually by determining the threshold FEC for which the observers could discriminate the test images from the original image. It was expected that higher CSF sensitivity would be associated with higher FEC's; and in fact, for images processed with low-pass (variable-window stimuli) CSF's, the threshold FEC's were larger for the higher-sensitivity (pattern-detection) CSF than for the lower-sensitivity (orientation detection) CSF. When two higher-sensitivity CSF's were compared, the bandpass (constant-window stimuli) CSF resulted in essentially the same FEC threshold as did the low-pass (variable-window stimuli) CSF. The fact that the FEC compensated for complex differences in the form of the CSF suggested that the discrimination task was mediated by a limited range of spatial frequencies over which the two CSF's were similar. Image contrast was then varied in order to extend the range of spatial frequencies tested. The FEC's estimated with the lower-contrast test images were unchanged for test images obtained with the high-sensitivity, bandpass CSF but increased for test images obtained with the high-sensitivity, low-pass CSF. These results suggest that peripheral contrast sensitivity as used in the present discrimination task is based on a high-sensitivity, bandpass CSF. The peripheral-vision model validated by the present analysis has practical applications in the evaluation of wide-field simulator images as well as area-of-interest or other foveating systems.

Adult↗

[Color vision defects in patients with arterial hypertension].

PURPOSE: In view of the generally impaired vascular condition in patients with arterial hypertension, we were interested in their colour perception. METHODS: Patients (n = 35, f:m = 14:21, mean age 52 +/- 11 years) with arterial hypertension without damage in end-organs and normal subjects (n = 62, :m = 28:34, mean age 49 +/- 9 years) as a control group were included in this study. Exclusion criteria were other systemic or ophthalmological diseases. In addition to the ophthalmological examinations (visual acuity, refraction, intraocular pressure, slit lamp and fundus examination) the colour vision was tested by the colour arrangement test Roth 28-hue (E) desaturated under standard conditions: The background used was black cardboard, illuminated by two Osram fluorescent lamps (L36 W/12LDL Daylight) providing 2000 lux at the test table. RESULTS: The ophthalmological examinations in the patients and in the control group were normal. The patients with arterial hypertension had a significantly higher mean error score (median +/- mean absolute deviation 150 +/- 56, Mann-Witney U-test: p < 0.001) in the colour arrangement test than the control group (median +/- mean absolute deviation 72 +/- 53.4). A particular colour axis (blue-yellow or red-green) was not found. CONCLUSION: Although the ophthalmological examinations were normal we found a disturbed colour vision in patients with arterial hypertension. This has to be taken into account in colour vision testing to avoid diagnostic interferences between specifically ocular diseases (e.g. glaucoma) and arterial hypertension.

Adult↗