Document Detail

Long-term renormalization of chromatic mechanisms following cataract surgery.
MedLine Citation:
PMID:  15518204     Owner:  NLM     Status:  MEDLINE    
The optical density of the human crystalline lens progressively increases with age, the greatest increase in the visible spectrum being at short wavelengths. This produces a gradual shift in the spectral distribution of the light reaching the retina, yet color appearance remains relatively stable across the life span, implying that the visual system adapts to compensate for changes in spectral sensitivity. We explored properties of this adaptive renormalization by measuring changes in color appearance following cataract surgery. When the lens is removed, cataract patients often report a large perceptual shift in color appearance that can last for months. This change in color appearance was quantified for four cataract patients (63-84 years) by determining the chromaticity of stimuli that appeared achromatic before surgery, and at various intervals after surgery for up to 1 year. Stimuli were presented on a calibrated CRT as 9.5-deg spots, with 3-s duration and 3-s interstimulus intervals (ISIs). Chromaticity was adjusted by the subjects in CIE L*a*b* color space with luminance fixed at 32 cd/m2, on a dark background. We also estimated the optical density of the cataractous lens by comparing absolute scotopic thresholds from 410 nm to 600 nm before and after surgery. The results demonstrated that immediately following surgery there is a large increase in the short-wave light reaching the retina, mainly below 500 nm. The achromatic settings generally showed an initial large shift in the "yellow" direction after surgery that gradually (but never fully) returned to the original achromatic point before surgery. The shifts in the achromatic point occur over a number of months and appear to occur independently of the fellow eye.
Peter B Delahunt; Michael A Webster; Lei Ma; John S Werner
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Visual neuroscience     Volume:  21     ISSN:  0952-5238     ISO Abbreviation:  Vis. Neurosci.     Publication Date:    2004 May-Jun
Date Detail:
Created Date:  2004-11-02     Completed Date:  2005-01-11     Revised Date:  2014-09-22    
Medline Journal Info:
Nlm Unique ID:  8809466     Medline TA:  Vis Neurosci     Country:  England    
Other Details:
Languages:  eng     Pagination:  301-7     Citation Subset:  IM    
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MeSH Terms
Adaptation, Ocular / physiology
Cataract Extraction*
Color Perception / physiology*
Discrimination (Psychology)
Lens, Crystalline
Postoperative Period
Time Factors
Visual Perception / physiology*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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