Three-Year Changes in Visual Function in the Placebo Group of a Randomized Double-Blind International Multicenter Safety Study: Analysis of Electroretinography, Perimetry, Color Vision, and Visual Acuity in Individuals With Chronic Stable Angina Pectoris

Abstract

Purpose To determine whether significant deteriorations in objective (electroretinography [ERG]) and subjective (standard automated and semi-automated kinetic perimetry; color discrimination; and best-corrected visual acuity) tests of visual function, potentially attributable to aging, occurred in the group randomized to placebo of a 3-year prospective multicenter ocular safety study of ivabradine for chronic stable angina pectoris. Methods The multicenter trial was conducted at 11 international ophthalmic centers. Changes in visual function between baseline and month 36 were analyzed by means of a two-tailed Wilcoxon signed-rank test, based on the Hodges and Lehman estimator of the median difference, with the 95% confidence intervals derived by Walsh averages. Results Thirty-eight participants from the placebo group completed the study (mean [SD], age, 62.7 [8.1] years). The group exhibited in each eye small, but statistically significant, reductions in the amplitudes of the dark-adapted (DA) ERG 3.0 a-wave, and light-adapted (LA) 3.0 b-wave, as well as increases in peak time for the DA 0.01 b-wave, DA 3.0 a-wave, LA 3.0 b-wave, and LA 3.0 30-Hz flicker response and in the isopter area I3e of the visual field. Conclusions Statistically significant deteriorations occurred in visual function over a period of 3 years, potentially attributable to age, within a group of individuals with chronic stable angina pectoris and unremarkable ophthalmological findings other than those attributable to age. Translational Relevance A longitudinal correction factor for age-related change in visual function may be useful in future trials to determine whether an observed deterioration in visual function is related to intervention or to aging.