Abstract
Purpose: :
, To compare optical coherence tomography (OCT)-measured retinal thickness with visual acuity in a pooled analysis of eyes with diabetic macular edema (DME) among study participants participating in one of 3 Diabetic Retinopathy Clinical Research Network randomized clinical trials.
Methods: :
Cross-sectional study of 2,058 eyes among 1,717 study participants enrolled in 3 randomized clinical trials (Protocols B, I, and J) evaluating treatments for DME. At baseline, retinal thickness was measured with a time domain (StratusTM, Carl Zeiss Meditec, Dublin, CA) OCT and visual acuity was measured with the electronic visual acuity (EVA) procedure.
Results: :
The correlation coefficient for visual acuity versus OCT central subfield was -0.36. The slope of the best fit line to the baseline data was approximately 3.3 letters (99% confidence interval, 3.8 to 2.8) decrease in visual acuity for every 100 µm increase in central subfield thickness. There were no obvious differences in correlation coefficients noted for subgroups based on prior treatment for DME or hemoglobin A1c levels.
Conclusions: :
There is a modest correlation between OCT-measured central subfield thickness and visual acuity. This pooled analysis is a confirmation of similar conclusions obtained from smaller data sets from a variety of investigators and provides an even greater confidence that OCT measurements of retinal thickness obtained on time domain OCT, while critical to provide an objective, reproducible and reliable measurement of retinal thickness, cannot substitute reliably as a surrogate for visual acuity in an individual at a given point in time.
Keywords: diabetic retinopathy • visual acuity • retina