Transient increase in flicker ERG amplitude preceding OCT-detected macular thickening in eyes with acute anterior uveitis

Abstract Purpose To determine the changes in amplitude of the flicker electroretinograms (ERGs) and central macular thickness (CMT) during the acute phase of acute anterior uveitis (AAU). Study design Retrospective case series. Methods Flicker ERGs (RETeval) and optical coherence tomographic (OCT) images were recorded from the affected and fellow eyes at multiple examination times. The outcomes are expressed as a ratio of the affected-to-fellow eyes (×100). The time courses were modeled by polynomial regression (degrees 1–4) with model selection based on R 2 , Akaike, or Bayesian information criteria (AIC, BIC), and the P values. The peak timing and uncertainty were estimated by patient-level cluster bootstrap resampling (B=2000). Results Eight eyes from eight patients (4 men, 4 women; mean age 48.8±15.8 years) underwent 3.3±1.0 paired ERG/OCT assessments. The ratio of the amplitudes of the two eyes had a significant nonlinear time course, and a 4th-degree model was best supported (R 2 =0.411, P =0.021). Bootstrap estimated an amplitude peak at 11.8 days (median 11.9; 95% CI 10.2–19.0) with a peak value of 134.6%. The ratios of the implicit times were not significantly associated with the disease duration. The CMT ratio had a significant nonlinear time course and a 2nd-degree model was best supported (R 2 =0.358, P =0.006). Bootstrap analyses estimated a CMT peak at 35.4 days (median 35.1; 95% CI 29.2–48.4) with a peak value of 108.6%. Conclusions The flicker ERG amplitudes increase transiently around two weeks after the onset of AAU and subsequent macular thickening in the OCT images. These findings suggest that flicker ERGs may serve as an early functional retinal marker of subclinical posterior segment inflammation in eyes with AAU.