Linked Life Data

10768021

Source:http://linkedlifedata.com/resource/pubmed/id/10768021

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2000-4-24
pubmed:abstractText
We investigated how the luminance of an immediate surround to a visual target affects the measurement of contrast sensitivity. We examined four young, healthy, subjects under typical lighting conditions for each test but varied the surround luminance systematically by controlling a backlit surround. The effect of varying the surround on contrast sensitivity measurements made with a Pelli-Robson chart was minimal. The only statistically significant difference was between measurements made with a 900 cd.m-2 surround compared to those made with 5.6, 9, or 30 cd.m-2 surrounds when tested at a viewing distance of 4 m. The higher luminance surround produced higher levels of contrast sensitivity. The effect of the surround luminance was greater when measuring contrast sensitivity to sinewave gratings using a method of constant stimuli. Optimum performance was found using a surround luminance of 9 cd.m-2 (20% of the mean target luminance). Statistically, a wide range of surround luminances (3-30 cd.m-2, or 7-67% mean target luminance) gave similar levels of visual performance, but higher luminance surrounds led to reduced contrast sensitivity. Possible reasons for the difference in the effect of the surround depending upon the test are discussed. Ophthalmic practitioners using contrast sensitivity measurements with letter charts probably need not make special efforts to illuminate the test surround appropriately. However, practitioners using sinewave gratings, especially computer generated sinewave gratings, to measure contrast sensitivity, may have their measurements affected by inappropriately lit task surrounds.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0275-5408
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
401-14
pubmed:dateRevised
2006-11-7
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
The effect of surround luminance on measurements of contrast sensitivity.
pubmed:affiliation
Department of Optometry, University of Bradford, UK. m.cox@bradford.ac.uk
pubmed:publicationType
Journal Article, Clinical Trial, Randomized Controlled Trial