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Your search keyword '"D. J. Powell"' showing total 3 results
Start Over Author "D. J. Powell" Journal british journal of ophthalmology
3 results on '"D. J. Powell"'

1. An automated statis perimeter/adaptometer using light emitting diodes

Author

W Ernst, Vaegan, D. J. Faulkner, D. J. Powell, C. R. Hogg, and Geoffrey B. Arden

Subjects
genetic structures, Dark Adaptation, Adaptation (eye), law.invention, Perimeter, Cellular and Molecular Neuroscience, Optics, Retinal Diseases, law, Automated static perimeter, Humans, Medicine, Photoreceptor Cells, Diode, business.industry, Sensory Systems, Dark-adapted, Ophthalmology, Wavelength, Sensory Thresholds, Minicomputers, Visual Field Tests, sense organs, Electronics, business, Photic Stimulation, Research Article, Light-emitting diode
Abstract

An automated static perimeter/adaptometer is described which measures thresholds with lights of 2 wavelengths. The instrument uses light-emitting diodes to produce the stimuli and is controlled by a small computer, making it very suitable for clinical testing of large numbers of patients. The use of 2 LEDs with different peak emission wavelengths (530 and 660 nm) permits an assessment of the relative state of rod and cone mechanisms in a particular region of the retina either during dark adaptation or when the eye is fully dark adapted.

Published
1983
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2. A modified ERG technique and the results obtained in X-linked retinitis pigmentosa

Author

W Ernst, D. J. Powell, M. P. Quinlan, A. L. Lyness, G. M. Clover, C. R. Hogg, R. M. Carter, and Geoffrey B. Arden

Subjects
Adult, RETINAL ABNORMALITY, Heterozygote, medicine.medical_specialty, X Chromosome, Adolescent, genetic structures, Genetic Linkage, Dark Adaptation, Audiology, Cellular and Molecular Neuroscience, Ophthalmology, Retinitis pigmentosa, Electroretinography, medicine, Humans, Photoreceptor Cells, Scotopic vision, Child, Relative amplitude, Aged, medicine.diagnostic_test, business.industry, Age Factors, Middle Aged, medicine.disease, eye diseases, Sensory Systems, Light intensity, Female, sense organs, X-linked retinitis pigmentosa, business, Retinitis Pigmentosa, Research Article, Photopic vision
Abstract

An electroretinographic (ERG) technique is described in which the relationship between scotopic b wave amplitude and stimulus light intensity is determined. The relative amplitude of scotopic to photopic responses is assessed by means of red light and flicker. The method is applied to the detection of ERG abnormalities in heterozygotes for X-linked retinitis pigmentosa. These have been found in only a proportion of cases. The ERG results can be used to suggest the nature of the retinal abnormality.

Published
1983
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