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At least 487 records · Page 27Linked to original sources
PubMed1998

Long-term postoperative results of a consecutive series of stages 4 and 5 retinopathy of prematurity.

OBJECTIVE: The purpose of the study was to assess the long-term, anatomic, and functional results of a consecutive series of stages 4 and 5 retinopathy of prematurity (ROP) eyes after surgical management. DESIGN: A retrospective analysis of 42 eyes of 21 children yielded 34 eyes of 19 children who were operated on for stages 4 and 5 ROP. PARTICIPANTS: In 33 of 34 eyes, it was possible to have age-appropriate vision testing. The children were followed for a mean of 44 months. RESULTS: Seventy-six percent of eyes (25 of 33) in which vision testing was possible had partial or complete attachment of the posterior pole. Fifteen percent of all eyes achieved 20/300 or better visual acuity. Thirty percent of all eyes achieved 20/800 or better visual acuity. Forty-eight percent of eyes achieved ambulatory vision of 20/ 1900 visual acuity or better, and 72% of eyes achieved light perception or better vision. All eyes were managed similarly for their preoperative screening, surgical therapy, and postoperative refractive correction by one vitreoretinal surgeon and one pediatric ophthalmologist. CONCLUSION: Timely surgical intervention and appropriate postoperative care can result in useful vision in stages 4 and 5 ROP.

Birth Weight↗
PubMedDate not supplied

The multifocal pattern electroretinogram in chloroquine retinopathy.

PURPOSE: Optimal screening for ocular toxicity caused by chloroquine and hydroxychloroquine is still controversial. With the multifocal pattern electroretinogram (mfPERG), a new electrophysiological technique has recently become available to detect early changes of ganglion cells. In this study this new technique is applied to a series of 10 patients seen consecutively receiving long-term chloroquine medication. METHODS: In 10 patients receiving chloroquine medication, clinical examination, Amsler visual field testing and computerized color vision testing were performed. If toxicity was suspected, automated perimetry was carried out. In addition, in all patients conventional pattern electroretinogram (PERG) and mfPERG testing were performed. RESULTS: On clinical examination 8 patients showed no chloroquine-associated maculopathy, while 2 patients did. Of these 2, only 1 reported abnormalities when viewing the Amsler chart, while automated perimetry showed typical, ring-like paracentral scotomas in both affected patients and color vision was significantly abnormal. In the normal patients, 4 of 8 had a mild color vision disturbance, which correlated to age-related macular changes. The amplitudes of the PERG and the central (approximately 10 degrees ) responses of the mfPERG were markedly reduced in chloroquine maculopathy, while the latencies were unchanged. The peripheral rings of mfPERG (ranging to 48 degrees ) were not affected by chloroquine toxicity. Both PERG and mfPERG were less affected by age-related macular changes. CONCLUSIONS: The reduction of PERG and central mfPERG responses in chloroquine maculopathy may help with the early detection of toxicity.

Adult↗
PubMed1983

Assessment and training of brain-damaged drivers.

This paper describes a driving assessment and training program that is primarily for patients discharged from the hospital and who may be experiencing residual impairment from some form of brain damage. Assessment is carried out by an occupational therapist and consists of several off-road tests (vision, reaction timing, computerized preview tracking test, general medical/psychological appraisal), and an on-road test. More than 300 patients have been seen since the program's inception in 1977, and trends indicated by their assessment results are: twice as many male as female referrals; a low fail rate among nonbrain-involved patients; diagnosis as a poor predictor of outcome; no significant difference between fail rates of right and left stroke patients; significant difference in average tracking task performance between the Pass, Borderline, and Fail assessment groups. Off-road testing complements, rather than replaces, on-road testing. Thirty-eight of the 300 patients were given special training, and 15 of these were unable to reach an acceptable level. This reflects a difficulty in predicting the outcome of unlicensed patients with severe disabilities.

Adolescent↗
PubMed2006

[Some remarks on the precision of visual acuity measurements].

BACKGROUND: Visual acuity measurements are used to determine the course of diseases, treatment outcomes, consequences of accidents, and the occupational ability of a patient. The fact, that visual acuity depends both on visual function as well as on the circumstances of examination, is often understood more intuitively than explicitly. Precision and accuracy of visual acuity measurements must be kept in mind, and occasionally need to be quantified and statistically evaluated, to avoid clinical errors. METHODS: Factors influencing acuity measurements are analyzed. Using appropriate examples the precision of acuity measurements is evaluated and quantified with standard vision test charts and threshold or staircase procedures. Limits of confidence and limits of tolerance are described for the statistical evaluation of consecutive visual acuity measurements. RESULTS AND CONCLUSIONS: The statistical evaluation of standard procedures is relatively time consuming, as 3 to 4 standardized measurements are needed on first examination and on follow-up. Threshold and staircase methods, however provide more feasible data, due to the examination technique. All evaluation procedures described here, can only be applied with logMAR acuity readings.

Confidence Intervals↗
PubMed1991

[A health center study].

The focus of this survey was the various sides of the work performed by the doctor at a child health center. One third of the children were referred to various specialists. In the case of five children in the physicians at the health center may have overlooked pathological disorder. This applied especially to the vision test at the age of four years. In twelve cases the parents failed to follow up special controls for their children. This again applied particularly to the follow-up of impaired vision. A thorough and correct vision test at the age of four years is recommended, as well as good follow-up routines for children at risk.

Ambulatory Care Facilities↗
PubMed2003

Animal colour vision--behavioural tests and physiological concepts.

Over a century ago workers such as J. Lubbock and K. von Frisch developed behavioural criteria for establishing that non-human animals see colour. Many animals in most phyla have since then been shown to have colour vision. Colour is used for specific behaviours, such as phototaxis and object recognition, while other behaviours such as motion detection are colour blind. Having established the existence of colour vision, research focussed on the question of how many spectral types of photoreceptors are involved. Recently, data on photoreceptor spectral sensitivities have been combined with behavioural experiments and physiological models to study systematically the next logical question: 'what neural interactions underlie colour vision?' This review gives an overview of the methods used to study animal colour vision, and discusses how quantitative modelling can suggest how photoreceptor signals are combined and compared to allow for the discrimination of biologically relevant stimuli.

Animals↗
PubMed1997

[Impairment of color vision in glaucoma].

The paper presents the historical evolution of knowledge about colour vision impairment in glaucoma, to the point where a peculiar type of chromatic disability has been delineated. Unlike other acquired defects, that of glaucoma implies predominantly the tritan axis, has a precocious onset and parallels the functional deficit of cones. Short-wave cones are predominantly affected. It is useful to associate colour vision tests with PEV and perimetry in investigating glaucoma at early stages.

Color Perception Tests↗
PubMed1990

Visual fitness to drive after stroke or head injury.

The visual requirements for driving in Britain are outlined and how they might be compromised following stroke or head injury examined. The role of the optometrist in assessing such patients who wish to resume driving is discussed. Topics discussed include legal considerations, the relationship between visual problems and driving ability and the vision-testing techniques that are most appropriate for use with the brain injured. An illustrative case history is presented.

Adult↗
PubMedDate not supplied

Artifacts in fusion and stereopsis testing based on red/green dichoptic image separation.

A red/green anaglyph stereotest (TNO) was administered to a group of patients who had anisometropic amblyopia, and the Worth 4-Dot test for fusion to two groups of strabismus patients. Both tests were administered twice, with the red/green lens position of the glasses reversed between eyes for the second administration. Twelve of 15 patients with anisometropic amblyopia exhibited a stereo acuity difference of 2:1 or more, and 18 of 89 strabismic patients changed Worth 4-Dot fusion or suppression status, between the two positions of the glasses. A group of seven strabismic patients who showed the reversal effect on the Worth 4-Dot test had the results of one glass' position discrepant with those of a geometrically identical achromatic test. It appears that the red/green format can introduce artifacts in binocular vision testing. Testing twice, with the red/green glasses reversed between trials, will prevent misinterpretation of binocular status and may provide diagnostically useful information.

Adolescent↗
PubMed1988

Binocular summation in humans: evidence for a hierarchic model.

1. Binocular summation was studied in human subjects using a batter of vision tests. Two tests assessed detection, another three acuity, one hyperacuity and one pattern recognition. 2. The magnitude of summation was consistent with, or exceeded, the level predicted from quadratic summation for both detection tests. 3. The summation factor was significantly smaller in the resolution tests than in the detection tests. Hyperacuity showed a large individual variation. 4. Spatial filtering of acuity targets did not influence summation. 5. No summation was found in the pattern recognition test. 6. It is argued that the degree of summation is related to the complexity of the visual task. A simple task yields a larger binocular summation than a more complex one. This may be related to the level of processing in the primary visual cortex.

Adult↗
PubMed1994

[Weak vision and blindness in the dog--a retrospective study].

Clinical-ophthalmological and electroretinographic results were found, compared and evaluated in 73 dogs of 21 different breeds with signs of decreased vision or blindness. Cataracts were found in 51 dogs. In cases of non visible fundus electroretinography is an essential tool for evaluation of the retinal function. Otherwise clinical-ophthalmological examination is a sufficient diagnostic method, except for sudden acquired retinal degeneration (SARD). The pupillary light reflex is an important diagnostic criterion for evaluation of the reflex pathway, but has less importance for diagnosis of visual abilities. These can be examined by vision tests. In English cocker spaniels and miniature and toy poodles with cataracts a significant electroretinographic loss of retinal function was found. In respect to the breed and age of these dogs this functional deficit is recognized as a result of progressive retinal atrophy.

Animals↗
PubMed2004

[Congenital achromatopsia: electroretinogram in early diagnosis].

PURPOSE: Achromatopsia is a hereditary disease responsible for congenital low vision. Patients present with nystagmus, abnormal visual behavior or photophobia. Only the electroretinogram (ERG) can confirm the diagnosis in infants. PATIENTS AND METHODS: Thirty children referred for nystagmus or low vision were included in this retrospective study. A complete ophthalmological examination, an ERG and when possible a color vision test (Ishihara, Farnsworth 15 Hue test) was done. A Ganzfeld ERG was performed in accordance with ISCEV standards in patients more than 6 years of age. In younger patients, a simplified method using electroluminescent diode stimulation was used and a comparative ERG in accordance with ISCEV standards was performed when the patients were old enough. RESULTS: The ERG response was identical in children and adults. It confirmed the diagnosis of achromatopsia: the scotopic components obtained in dark adapted conditions were normal, (scotopic a-wave, b2 wave). The photopic components, recorded in light-adapted conditions, in order to inhibit the scotopic response (photopic wave, b1 wave), were not recordable. The color vision tests confirmed color blindness; however, in some patients color denomination was correct. CONCLUSION: The simplified ERG procedures performed in our series were reliable in detecting achromatopsia. However, it may not be sufficient to discriminate complete from incomplete achromatopsia.

Adolescent↗
PubMedDate not supplied

A novel mutation in the short-wavelength-sensitive cone pigment gene associated with a tritan color vision defect.

Inherited tritan color vision deficiency is caused by defects in the function of the short-wavelength-sensitive (S) cones. This heterozygous group of disorders has an autosomal dominant pattern of inheritance. Amino acid variations of the S cone opsin are rare and all that have been identified thus far are associated with inherited tritan color vision defects. Here we report the identification of a 30-year-old male who made errors on standard color vision tests consistent with the presence of a mild tritan color vision deficiency. We tested the hypothesis that his color vision impairment was due to a mutation in the S cone photopigment gene. He was found to be heterozygous for a mutation that caused the amino acid proline to be substituted in place of a highly conserved leucine at amino acid position 56 in the S cone opsin. This mutation was absent in 564 S cone photopigment genes from 282 subjects who did not make tritan errors. Thus, we conclude that this mutation disrupts the normal function of S cones.

Adult↗
PubMed1991

Accommodative performance for chromatic targets in diabetes mellitus: a preliminary report.

Our objective was to evaluate the diagnostic potential of a new vision testing procedure for detecting subclinical visual dysfunction in patients with insulin-dependent diabetes mellitus (IDDM) and minimal or absent retinopathy. We used a method which challenged both the ocular focusing and color discrimination systems simultaneously. A computerized laser speckle optometer which measured changes in ocular refraction on a subjective criterion of speckle movement rather than perceived blur was used to measure the accuracy of steady-state accommodative responses. Five volunteers between 15 and 23 years of age who had IDDM and minimal background retinopathy participated in this study. Our results for this small group of diabetics showed that: (1) the overall binocular accommodative response profiles of diabetics for colored targets through increasing negative power ophthalmic lenses did not differ markedly from those of a control population; (2) diabetics exhibited a high sensitivity for perception of optical defocus; (3) the blood glucose level influenced the extent and accuracy of accommodative responses; and (4) the overall accommodative precision, when compared to a group of nondiabetics in the same age range, showed evidence of being more reliant on target colors. The theoretical and clinical implications of these findings are discussed.

Accommodation, Ocular↗
PubMed1985

Differential diagnosis of congenital tritanopia and dominantly inherited juvenile optic atrophy.

To determine whether congenital tritanopia and dominantly inherited juvenile optic atrophy (DIJOA) are the same clinical entity, we used electroretinograms of the blue-sensitive cone system (blue cone ERGs), comparing those of two patients with congenital tritanopia from two pedigrees with those of four patients with DIJOA from two pedigrees. The examinations also included visual acuity and visual field tests, fundus examination, the dark-adaptation test, and several color vision tests. The blue cone ERG confirmed a difference between the two groups; it was unrecordable in the patients with congenital tritanopia but within the normal range in those with DIJOA. We believe that congenital tritanopia and DIJOA are distinct disease entities and that the blue cone ERG is a key factor in the differential diagnosis.

Adult↗