Document Detail

Effect of stimulus size on static visual fields in patients with retinitis pigmentosa.
MedLine Citation:
PMID:  11013205     Owner:  NLM     Status:  MEDLINE    
PURPOSE: To determine the effect of stimulus size on sensitivity of patients with retinitis pigmentosa (RP) as measured by automated static perimetry.
DESIGN: Comparative case series.
PARTICIPANTS: Thirty-nine patients with RP and a control group of 10 healthy volunteers.
METHODS: Automated static perimetry (full threshold programs 24-2 or 30-2) was performed twice on one eye of each participant using stimulus sizes III (0.43 degrees diameter) and V (1.72 degrees diameter). Data from the same 50 test locations were used from each field.
MAIN OUTCOME MEASURES: At each location, for each participant, the size effect was computed as the difference (in decibels) in sensitivities for sizes V and III, and the average sensitivity was computed as the mean of sensitivities for the two sizes.
RESULTS: For both patient and control groups, the size effect was negatively correlated with average sensitivity (r(2) > 0.124; P: < 0.001). The mean size effect was significantly greater for the patient group than for the control group: 8.6 (+/- 3.6) dB versus 5. 4 (+/- 2.2) dB (t = 18.0; P: < 0.001). The percentage of abnormal locations (more than 8 dB below mean normal) tended to be lower for size V than for size III, with a mean of 67% for size V versus 95% for size III. The percentage of absolute defects was also lower for size V than for size III, with a mean of 35% for size V versus 54% for size III.
CONCLUSIONS: In damaged regions of the visual fields of patients with RP, increase in stimulus size from III to V can produce abnormally large increases in perimetric sensitivity. Size III may be more useful than size V for detection of field abnormality, whereas size V may be more useful than size III for observing progression of advanced RP.
W H Swanson; J Felius; D G Birch
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Ophthalmology     Volume:  107     ISSN:  0161-6420     ISO Abbreviation:  Ophthalmology     Publication Date:  2000 Oct 
Date Detail:
Created Date:  2000-10-17     Completed Date:  2000-10-17     Revised Date:  2014-09-15    
Medline Journal Info:
Nlm Unique ID:  7802443     Medline TA:  Ophthalmology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1950-4     Citation Subset:  IM    
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MeSH Terms
Retina / physiopathology*
Retinitis Pigmentosa / genetics,  physiopathology*
Sensitivity and Specificity
Visual Field Tests / methods*
Visual Fields / physiology*
Grant Support
EY05235/EY/NEI NIH HHS; EY07716/EY/NEI NIH HHS; R01 EY007716/EY/NEI NIH HHS; R01 EY007716-09/EY/NEI NIH HHS; R01 EY007716-10/EY/NEI NIH HHS

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

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