This Article  • Full text  • PDF  • Reply to article  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Contact me when this article is cited  Related Content  • Similar articles in this journal  Topic Collections  • Statistics and Research Methods  • Glaucoma  • Alert me on articles by topic

A Comparison With Size III Stimuli

Michael Wall, MD; Caridad F. Brito, PhD; Kimberly R. Woodward, MS; Carrie K. Doyle, MS; Randy H. Kardon, MD, PhD; Chris A. Johnson, PhD

Arch Ophthalmol. 2008;126(4):473-479.

Objective  To compare empirical probability plots in patients with glaucoma for size V and III perimetry testing.

Methods  We computed empirical probability plot percentile limits after testing 60 age-matched controls tested with both size III (Swedish interactive thresholding algorithm) and size V (full threshold) perimetry twice. Probability plots of 120 patients with glaucoma tested in the same way were computed. We compared the number of abnormal test locations in the 2 stimulus sizes; we then compared these results with those from size III StatPac software (Zeiss Humphrey Systems, Dublin, California) using 2-way repeated-measures analysis of variance.

Results  We found a similar number of abnormal test locations (P  .05) for the size III and size V testing conditions identified by the probability plots (no significant difference); there were significantly fewer abnormal locations using StatPac (size III) than from our size III database. When results were stratified by mean deviation, the mild visual loss group again did not show any significant differences between sizes III and V.

Conclusions  Size V full-threshold testing gives a similar number of abnormal test locations in patients with glaucoma compared with the size III Swedish interactive thresholding algorithm standard test. Size V testing, with its greater dynamic range and lower variability, may be a viable alternative to size III testing in patients with glaucoma.

Author Affiliations: Departments of Neurology (Dr Wall) and Ophthalmology (Drs Wall, Kardon, and Johnson, and Mss Woodward and Doyle), University of Iowa, College of Medicine, Veterans Administration Hospital, Iowa City; Department of Psychology, Eastern Illinois University, Charleston (Dr Brito); and Discoveries in Sight, Devers Eye Institute, Portland, Oregon (Dr Johnson).