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At least 829 records · Page 46Linked to original sources
PubMed1991

[Visual function requirements in modern aviation].

The authors describe aviation ophthalmology as a typical ergoophthalmic discipline as regards the sphere of interest as well as with regard to its preventive trend. The visual analyzer is a very exposed sense which can be modified by some dynamic effects of flight to such an extent that they may restrict the pilot's activities and consequently also the safety of the flight. Specific factors of flight which comprise also aerogenic hypoxia, hypobarism, overloading, vibrations and the consequences of impaired relations of the different senses may be manifested by changes of the perception of light, colour, visual acuity, perception of contrasts of the visual field etc. The most modern aviation technique puts some so far unusual demands on vision tested by means of complicated psychophysiological tests. Only the future will show which tests should be included among routine methods of aviation ophthalmology and which tests will be restricted only to experimental work.

Aerospace Medicine↗
PubMed2005

Visual function assessment and metamorphopsia after macular hole surgery.

The purpose of this study was to develop a new resolution acuity measure for patients after macular hole surgery. Fifty eyes of 44 patients who had undergone successful treatment were tested. Visual acuity was measured with the Snellen, Early Treatment of Diabetic Retinopathy Study and Landolt-C charts. A Line Resolution Test was performed as part of their follow-up exam where a vertical line was presented. Participants were categorized by their perception of the line as solid, bent or broken. The line could be distorted into a sine-wave pattern in order to determine the participants' detection threshold for the distortion. Chart acuities did not differ among the three groups, as categorized by their line perception. Only the distortion measure was sensitive enough to differentiate the solid- from the broken-line group. The distortion measure assesses resolution power of the macula in smaller increments than acuity charts. This hyperacuity approach is more appropriate in the assessment of functional outcome after microsurgery.

Aged↗
PubMed1995

Electrophysiological exploration of visual function in mitochondrial diseases.

In a group of 10 children (ranging from 5 months to 15 years old) affected by diseases with mitochondrial dysfunction, 4 suffered from mitochondrial myopathy, 4 from mitochondrial encephalopathy and 2 from Friedreich's ataxia. The clinically detectable visual impairment consisted of 3 grey ocular fundi (the other 7 were normal) associated, in 2 subjects, with a mild nystagmus. Electrophysiological assessment, consisting of ERGs and flash VEPs, was systematically performed. The normal ERGs in all subjects confirmed the normal functioning of retinal electrogenesis. In contrast, the VEPs of 6 out of 10 subjects were modified: in 2 of the 4 subjects with mitochondrial myopathy, the VEPs had a hyperamplitude; in the 2 subjects with Friedreich's ataxia, the implicit time of the principal VEP peaks was increased, together with a hyperamplitude in 1 case; lastly, in 2 of the 4 subjects with mitochondrial encephalopathy, the VEPs were altered. These modifications reflected visual pathway conduction disorders with no clinical expression. Various underlying pathophysiological mechanisms possibly responsible for these modifications are discussed.

Adolescent↗
PubMed1987

Assessment of visual function in MS patients: comparative study of some diagnostic tests.

Optic pathways are frequently involved in Multiple Sclerosis (MS). However, in some cases the involvement is asymptomatic or gives rise to only slight visual disturbances without alterations of visual acuity or of clinically evident visual field defects. In these cases several diagnostic tests permit an objective evaluation of the visual dysfunction. The aim of this study is to compare the value of contrast sensitivity test (CST), pattern reversal visual evoked potential (VEP), ophthalmoscopy, Goldmann perimetry in 45 MS patients with normal visual acuity. Examination of contrast sensitivity was carried out with a simple two-alternative forced choice test estimating the spatial frequency of 4 cycles/degree. The VEP was performed with a pattern reversal checkerboard at a spatial frequency of 1 and 2 cycles/degree. Fundus examination was abnormal in 12 patients; visual field defects were detected in 16 patients. 32 patients (71.1%) had abnormal CST in one or both eyes. VEP for the 30' checks was abnormal in 32 cases (71.1%) and that for the 15' checks in 36 cases (80.0%). All but 4 patients (91.2%) had one or more abnormal tests. All patients with abnormal perimetry and/or fundus examination had also CST and/or VEP altered. It is apparent that CST and VEP reveal a significant proportion of abnormalities in the visual system that have not been revealed by routine neuroophthalmological examination.

Adolescent↗