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At least 487 records · Page 27Linked to original sources
PubMed1988

Binocular interaction and steady-state visual evoked potentials. I. A study in normal subjects and in subjects with defective binocular vision.

A correlate of binocular-neuron activity was found in some properties of visual evoked potentials (VEPs), such as facilitation (defined as a binocular response greater than the sum of the monocular responses) and changes in latency (shortening of binocular VEP latency as compared to that of monocular VEPs). Monocular and binocular steady-state VEPs in response to phase-alternating gratings of different contrast and both spatial and temporal frequency were recorded in three normal subjects. Fourier analysis of the responses was performed to isolate the component at the reversal frequency. Binocular VEPs showed facilitation in the low-contrast range (3%-10%). Facilitation was highest for gratings that had spatial frequency of 0.6-2 cycles/degree (c/d), alternating at 16 reversals per second. Phase shortening was found across a parameter range larger than that at which amplitude facilitation occurred. These results suggest that both amplitude facilitation and phase shortening in binocular VEPs may provide an objective measure of binocular visual function in clinical ophthalmology.

Contrast Sensitivity↗
PubMed1988

Fusion ability lost and regained in visual adults.

The case reports are given of two adult patients who lost all fusion ability and had the signs and symptoms of central fusion disruption and intractable diplopia. Both patients suffered binocular sensory deprivation for several years caused by a combination of a traumatic cataract and uncorrected unilateral aphakia. One patient had a posterior chamber intraocular lens inserted to correct the aphakia and the other patient had a contact lens. Aniseikonia was not appreciated by either patient and did not appear to contribute to the fusion problem. Adjustable strabismus surgery, in both patients, and prism glasses, in one, enabled approximate superimposition of the visual axes. After several months, both patients began to develop some fusion with small amplitudes and the vertical bobbing typical of central fusion disruption disappeared.

Adult↗
PubMed1996

Evaluation of a new E-optotype chart for measuring contrast sensitivity.

BACKGROUND: Clinical examinations of the contrast sensitivity (CS) are currently made by one-trial measurements of a restricted number of spatial frequencies around the peak of the CS function (CSF). These methods do not allow calculation of the confidence intervals of the single measurements, thus preventing examiners from evaluating the reliability of their data. We elaborated a new method of CS measurement at the peak of the CSF, aiming at economical clinical applicability together with enhanced reliability. Moreover, we tried to establish lower limits of normal CS that would allow classification of low test results as pathological. METHODS: A chart containing six columns of E optotypes of constant size and decreasing contrast (from about 16% to 0.5%) was used to perform six-fold contrast threshold determination (method of descending limits, forced choice). Optotype dimensions are intended to measure the CS at spatial frequencies corresponding to 3 and 6 cycles per degree (c/deg). The reference values were defined by testing 61 normal subjects: 31 "young" (16-35 years) and 30 "old" (56-81 years). RESULTS: The mean logCS found in the young group was 2.07 +/- 0.086 SD for 3 c/deg and 1.94 +/- 0.154 SD for 6 c/deg, while in the old group the mean logCS was 1.88 +/- 0.095 SD and 1.74 +/- 0.118 SD respectively. CONCLUSION: This simple method of measuring CS can provide a single CS value together with a confidence interval for the individual patient, thus allowing evaluation of measurement reliability.

Adolescent↗
PubMed1975

[Posttraumatic unilateral aphakia and contact lens -binocular functions of grown-ups].

The binocular results are only subnormal and comparable to former squinting patients. The results are better if one succeeds in reaching a visual acuity of at least 1.0. One can try to prevent a divergence by prescribing a contact lens as early as possible. Presbyopic patients have better binocular functions because the lost accommodation is the most interfering component (factor). It has disadvantageous effects especially on those patients who are yet presbyopic. The aniseikonia is in contrary to this not an as important interfering factor.

Accommodation, Ocular↗
PubMed1975

[Fixation disparity under various test-conditions (author's transl)].

Measurements of fixation disparity and Panum areas were performed with a special device of the phase-difference haploscope in normal persons. There was a reproduceable influence on fixation disparity and size of Panum areas, when the conditions of examination were changed (position of the binocular fusion-pattern, brightness and contrast of the targets for sensory fusion and time of prism wearing). There found we found only under comparable conditions a quantitative relationship between the two phenomenons.

Adaptation, Ocular↗
PubMed1990

Long-term observation of endocrine ophthalmopathy and retrospective appraisal of therapeutic measures.

The course of endocrine ophthalmopathy was investigated on the basis of clinical and biochemical parameters and in relation to different therapeutic strategies. A retrospective appraisal was made of 297 patients (44 +/- 14 yr, 249 women) with inclusion of anamnestic and clinical data as well as the results of computer tomography. At the beginning of therapy, 253 patients were hyperthyroid, 36 were euthyroid and eight were hypothyroid. The HLA typing carried out in 89 patients showed the phenotypes B8 and DR3 in 32% and 42% of the cases, respectively. Raised microsomal antibodies were present in 56% of the patients and there were raised thyroglobulin antibodies in 19%. Sixty-three % of the patients received immunosuppressants in the course of therapy: glucocorticoids in all cases, nonsteroid immunosuppressants in 15%. Eight % of the patients were irradiated retrobulbarly. The inflammatory parameters could be favorably affected, whereas eye muscle involvement and bulbar protrusion proved to be more resistant to therapy. In patients with combined immunosuppressant therapy or steroids + retrobulbar radiation, there were unequivocal successes with regard to the proptosis, vision and intraocular pressure. None of the strategies applied constitutes an optimal treatment with regard to the long-term course. Following therapy, there is an improvement of endocrine ophthalmopathy, but not complete healing.

Adolescent↗
PubMed2004

[Clinical and genetic findings in a patient with fundus albipunctatus].

METHODS: The 38-year-old index patient was examined by visual acuity testing, perimetry, dark adaptometry, funduscopy, electroretinogram (ERG), and multifocal ERG. She was screened for mutations in exons 2-5 and exon/intron boundaries of the 11- cis retinol dehydrogenase gene by direct sequencing. RESULTS: Visual acuity was 1.0, but perimetry revealed paracentral scotomas associated with reading problems. The optic discs were normal. After 45 min of darkness there was nearly no increase of light sensitivity. After 30 min of dark adaptation, the scotopic ERG showed reduced amplitudes, but after 60 min a nearly normal level was reached. The 30-Hz flicker response of the cone ERG showed borderline implicit times, but no reduction of amplitudes. However, multifocal ERG clearly disclosed a paracentral amplitude reduction as the reason for the visual field defects. The fundus was typical for fundus albipunctatus. The patient is a compound heterozygote carrying a Ile33Asn and a Arg157Trp mutation. CONCLUSIONS: The paracentral visual field defects were due to cone dysfunction. So far the patient exhibits no cone dystrophy.

Adult↗
PubMed2005

[Influence of cutoff filters on reading behavior in age-related macular degeneration].

BACKGROUND: Cutoff filters may improve contrast sensitivity in different retinal dystrophies and therefore lead to improved visual function. We investigated whether cutoff filters result in improved reading ability in age-related macular degeneration (AMD). METHODS: Reading performance was examined in 22 patients with AMD aged 63-91 years (visual acuity 0.1-0.5) using the Radner reading charts. These charts were presented in random order either with or without cutoff filters (Zeiss CF 540 and CF 580) monocularly to the better eye using a defined luminance of the test charts of 105 cd/m(2). RESULTS: Using the CF 540 cutoff filter, there was no significant change in visual acuity while there was a tendency to decrease. Calculating the LogRAD score, which takes reading errors into account, three patients improved by one line, while nine deteriorated, six of them by one line or more. There was no significant improvement using the CF 580 compared to either the CF 540 or to normal reading glasses. CONCLUSIONS: Overall, we found no measurable improvement using the CF 540 cutoff filter. The cutoff filter CF 580, tested for additional comparison, did not show any advantage.

Aged↗