Abstract
Purpose :
To investigate contrast sensitivity (CS) in glaucoma patients with advanced visual field damage from glaucoma, and to evaluate the precision of two clinical CS tests.
Methods :
Thirteen patients with advanced open-angle glaucoma (median age, 68 y, range 47 to 100 y); visual field Mean Deviation, median -28.8 dB, range -31.2 to -21.3 dB; best-corrected visual acuity (BCVA), median +0.10 logMAR (range, 0.00 to +0.28 logMAR) underwent CS testing with the Pelli-Robson (PR) chart (Precision Vision, IL, USA; distance, 1 m) and the Freiburg Visual Acuity and Contrast Test (FrACT, http://michaelbach.de/fract/, version 3.9.3; distance, 1.60 m). Retest measurements were obtained after one week.
Results :
Median contrast sensitivity was 1.30 log units (range, 1.05 to 1.65 log units) with the PR chart and 1.35 log units (range, 1.00 to 1.90 log units) with FrACT. Visual acuity explained <50% of the variance in contrast sensitivity.
CS estimates of both tests were closely related (Spearman rank correlation coefficient, 0.86), but CS was 0.08 log units higher with FrACT (median; 95% CI, -0.02 to 0.16 log) than with the PR chart, and Bland-Altman 95% repeatability intervals appeared slightly tighter with the PR chart (Figure).
Conclusions :
All patients were able to perform both tests, and almost all patients showed moderate or profound deficits in contrast sensitivity (normal value, ~1.70 log units) despite near-normal visual acuity. Contrast sensitivity should be routinely evaluated alongside visual acuity to monitor foveal visual function in patients with advanced glaucoma.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.