advertisement
Abstract #6047 Published in IGR 2-2
Quantitative comparison of static perimetric strategies in early glaucoma: test-retest variability
Spry PGD; Henson DB; Sparrow JM; North RVJournal of Glaucoma 2000; 9: 247-253
PURPOSE: The aim of this study was to describe and compare test-retest variability of threshold-related suprathreshold and threshold examination strategies. METHODS: Threshold-related suprathreshold and Fastpac threshold central visual field examinations were performed twice (test and retest) within a four-week period on 322 subjects with early to moderate primary open-angle glaucoma and glaucoma suspects. For both strategies, defects were quantified by a count, or score, of the number of defective locations within the field as a whole and by hemifield, thereby providing a simple measure of defect extent. This quantification was obtained for the suprathreshold strategy at three suprathreshold increments (5, 8, and 12 dB), and for the full threshold strategy at two levels of pattern deviation probability, although absolute full threshold defect depth was not considered. Mean rest-retest score differences and spread of score differences were used to describe variability. An index of relative variability was used to compare the two visual field examination strategies. RESULTS: Marked degrees of defect extent variability were found to exist in both suprathreshold and Fastpac examination strategies. In general, the suprathreshold strategy exhibited lower test-retest variability of defect extent than the Fastpac strategy. Suprathreshold test variability was dependent on the suprathreshold increment. Fastpac examination variability was independent of defect depth when analyzed on the basis of pattern deviation probability values, and was also found to be independent of the area of visual field loss. CONCLUSIONS: Suprathreshold examination techniques may provide a reliable perimetric alternative to thresholding strategies for monitoring individuals with early and moderate glaucoma, although they may not be suitable for individuals with advanced glaucomatous visual field loss.
Dr. P.G.D Spry, Discoveries in Sight, Devers Eye Institute, 1225 NE 2nd Avenue, Portland, OR 97232, USA
Classification:
6.6.2 Automated (Part of: 6 Clinical examination methods > 6.6 Visual field examination and other visual function tests)
