Impact of cataract on the results of frequency-doubling technology perimetry☆
Presented in part at: Association for Research in Vision and Ophthalmology Annual Meeting, March, 2002; Fort Lauderdale, Florida.
Received 6 October 2003; accepted 15 January 2004.
Abstract
Purpose
To determine the effect of cataract on the results of frequency-doubling technology (FDT) perimetry.
Design
Consecutive cohort study.
Participants
Forty-four patients with normal ophthalmic examinations, with the exception of cataract, scheduled to undergo phacoemulsification and posterior chamber lens implantation were prospectively identified and completed the study.
Methods
All subjects underwent FDT perimetry using the full-threshold C-20 strategy. Both eyes were tested within 1 month before cataract surgery and up to 3 months after surgery. The unoperated fellow eyes served as controls.
Main outcome measures
Changes in visual acuity (VA), mean deviation (MD), and pattern standard deviation (PSD) were evaluated. For each subject, the change in MD and PSD in the eye that underwent cataract surgery was adjusted for change in the control eye that is thought to occur due to a learning effect.
Results
Among the eyes that underwent cataract surgery, the median preoperative VA was 20/60 (range, 20/30–20/800) and the mean preoperative MD was −4.00±3.72 decibels (dB). Postoperatively, the median VA improved to 20/30 (range, 20/20–20/70) and the mean postoperative MD was −0.26±3.09 dB (P<0.001). Among the control eyes, MDs were −1.74±3.71 dB preoperatively and −0.94±3.85 dB postoperatively (P = 0.019). The adjusted improvement in MD among eyes that underwent cataract surgery was 2.94±3.44 dB (P<0.001). There was no significant change in PSD. Preoperative VA correlated significantly with preoperative MD (r = 0.39, P = 0.01). The improvement in VA correlated significantly with the adjusted improvement in MD (r = 0.38, P = 0.01).
Conclusions
Cataract has an adverse effect on the MD but not the PSD in FDT perimetry. Among eyes with visually significant cataract, the MD correlates significantly with VA. After cataract surgery, the change in VA correlates significantly with the adjusted change in MD.
1Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IllinoisUSA
Correspondence to Angelo P. Tanna, MD, 303 East Chicago Avenue, 5-715, Chicago, IL 60611, USA.
ABSTRACT