Despite their normal or near-normal Snellen visual acuity, patients with glaucoma often complain of “poor” vision.
To investigate the relationship between large-letter contrast sensitivity, high-contrast visual acuity, and visual field defects in patients with glaucoma who have 20/40 or better visual acuity.
Prospective, cross-sectional case series.
We evaluated 250 eyes of 144 subjects from the Glaucoma Service at the University of Illinois at Chicago College of Medicine. Subjects with a diagnosis of glaucoma, suspected glaucoma, or ocular hypertension who met the 20/40 or better vision requirement were recruited. Visual acuity was measured using the rear-illuminated Lighthouse Visual Acuity Chart at 4 m. Contrast sensitivity was measured using the Pelli-Robson Chart in a front-illuminated box with even luminance across the chart. Visual fields of the patients were measured using the 24–2 full-threshold program on the Humphrey Visual Field Analyzer.
A significant correlation (r = 0.57, P < 0.001, n = 127) was found between the visual field mean deviations and the contrast sensitivity scores. The correlation (r = −0.322, P < 0.001, n = 127) was less between the visual field mean deviation and the log MAR visual acuity values, as was the correlation between the contrast sensitivity scores and log MAR visual acuity values (r = −0.370, P < 0.001, n = 127). In the subgroup of patients with chronic open-angle glaucoma, the correlation between the mean visual field deviation and the contrast sensitivity score was higher at 0.689 (P ≤ 0.001, n = 62).
Reduced contrast sensitivity is significantly correlated with visual field losses in patients with glaucoma and a visual acuity of 20/40 or better. The study data support the conclusion that, compared with visual acuity, the disease process preferentially affects contrast sensitivity. In our previous work, contrast sensitivity was shown to be more related than visual acuity to real-world function in patients with early glaucomatous changes.
*Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, and †Research and Development Service, Chicago Veterans Administration Health Care System, West Side Division, Chicago, Illinois
Received July 23, 2002;
sent for revision September 9, 2002; accepted December 2, 2002.
Presented in part as a poster at the Association for Research in Vision and Ophthalmology Annual Meeting, Fort Lauderdale, FL, April 30 to May 4, 2001, and at the American Ophthalmological Society, Hot Springs, VA, May 20–23, 2001.
Supported in part by the Carson Gabriel Fund, Chicago, IL, a departmental grant from Research To Prevent Blindness, New York, NY, and The Department of Veterans Affairs, Rehabilitation Research and Development Service, Washington, DC.
Address correspondence and reprint requests to J. T. Wilensky, MD, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, 1855 W. Taylor Street, Suite 2.10, Chicago, IL 60612. E-mail: Jacowile@UIC.edu