Contrast Sensitivity as an Independent Measure of Foveal Function

Identifier 19840118_nanos_sciplatform1_05
Title Contrast Sensitivity as an Independent Measure of Foveal Function
Creator James A. Goodwin, MD, University of Illinois Hospital
Subject Contrast Sensitivity; Foveal Function; Independent Measure
Description During recent years there has been a burgeoning interest in contrast sensitivity measurement as a parameter of foveal function. Typically sine wave gratings are presented on a TV monitor or oscilloscope and the just visible contrast between dark and light bars is established as a threshold value. The threshold varies with fineness of the grating so it is useful to measure a series of thresholds with gratings of different "spatial frequency". Fine gratings have many bars per unit visual angle and are described as having high spatial frequency while coarse gratings of low spatial frequency have few bars per unit visual angle. The human visual system is most sensitive for gratings around 4 cycles/degree and is less sensitive (requires higher contrast to achieve threshold) at lower and higher spatial frequencies. Snellen visual acuity is tested with maximum contrast black on white figures having sharp edges (square wave function) and the stimulus is made progressively finer (analogous to higher spatial frequencies for a repetitive stimulus like a grating) until the just visible fineness threshold is reached. Thus Snellen acuity constitutes but a single point on the curve relating contrast sensitivity to spatial frequency and in this sense the contrast sensitivity curve is an expanded measure of foveal function as compared with the Snellen threshold.
Relation is Part of NANOS 1984: Platform Presentations (Session I)
Contributor Primary Wirtschafter, Jonathan D
Publisher Spencer S. Eccles Health Sciences Library, University of Utah
Date 1984-01-18
Type Text
Format application/pdf
Format Creation application/pdf
Source 1984 North American Neuro-Ophthalmology Society Annual Meeting
Rights Management North American Neuro-Ophthalmology Association (NANOS), Copyright 1984. For further information regarding the rights to this collection, please visit http://library.med.utah.edu/NOVEL/about/copyright
Holding Institution North American Neuro-Ophthalmology Association. NANOS Executive Office 5841 Cedar Lake Road, Suite 204, Minneapolis, MN 55416
Collection Neuro-Ophthalmology Virtual Education Library: NOVEL, NANOS Annual Meeting, https://novel.utah.edu/collection/NAM/index/
Language eng
ARK ark:/87278/s6mk9kmg
Setname ehsl_novel_nam
Date Created 2014-03-21
Date Modified 2014-03-21
ID 183662
Reference URL https://collections.lib.utah.edu/details?id=183662
Back to Search Results