Preoperative Electrophysiological Characterization of Patients with Primary Macula-involving Rhegmatogenous Retinal Detachment

Abstract

Purpose: To determine 1) which components of retinal function are impaired after rhegmatogenous retinal detachment, 2) which outer retinal pathways (rod- or cone-driven) are more severely affected, and 3) whether there is concomitant inner retinal dysfunction.

Methods: We conducted a prospective observational study in a large academic institution. We performed preoperative electroretinography on eight patients to assess outer and inner retinal function. In all cases, a comparison between the eye with the detached retina and the control fellow eye was made.

Results: Eyes with a detached retina had significantly lower a-wave and b-wave amplitudes with respect to both rod- and cone-dominated testing parameters (P < 0.05) and reduced 30 Hz flicker responses compared to fellow eyes (P < 0.05); the effect size was similar for all significantly reduced parameters (r~0.6). There were no significant differences between eyes with detached retinas and control fellow eyes with respect to b/a-wave ratios, a-wave latencies, or b-wave latencies.

Conclusion: Patients with rhegmatogenous retinal detachment have preoperative outer retinal dysfunction equally affecting both rod- and cone-driven pathways, and they have minimal inner retinal dysfunction.

Keywords: Clinical Electrophysiology; Electroretinography; Retinal Detachment.

Figure 1

On preoperative electroretinography, eyes with detached retinas exhibited significantly reduced a- and b-wave amplitudes compared to fellow control eyes at 0.01 cd·s/m² (a and b), 0.50 cd·s/m² (c and d), and 3.0 cd·s/m² (e and f) flash intensities. Open circles depict individual data points; horizontal lines depict medians (a–f) (*P < 0.05).

Figure 2

On preoperative electroretinography, eyes with detached retinas exhibited significantly reduced a- and b-wave amplitudes compared to fellow control eyes at the 3.0 cd·s/m² flash intensity under 30 cd/m² background (bkgd) illumination (a and b) and decreased peak amplitudes in response to 30 Hz flicker (c). Open circles depict individual data points; horizontal lines depict medians (a–c) (*P < 0.05).

Figure 3

On preoperative electroretinography, the b/a-wave ratios in eyes with detached retinas were similar to those in fellow control eyes at 0.01 cd·s/m² (a), 0.50 cd·s/m² (b), and 3.0 cd·s/m² (c) flash intensities, and at 3.0 cd·s/m² flash intensity under 30 cd/m² background (bkgd) illumination (d). Open circles depict individual data points; horizontal lines depict medians (a–d).

Figure 4

. On preoperative electroretinography, there were no differences between eyes with detached retinas and fellow control eyes with respect to a- (a) or b-wave (b) latencies at 0.01 cd·s/m², 0.50 cd·s/m², or 3.0 cd·s/m² flash intensities, or at 3.0 cd·s/m² flash intensity under 30 cd/m² background (bkgd) illumination. Open circles depict individual data points; horizontal lines depict medians (a and b).

Figure 5

Dichotomizing study eyes based on the extent of retinal detachment (i.e., ≤6 clock-hours or ≤50% detached (det) versus >6 clock-hours or >50% det) revealed a pattern of step-wise decline in preoperative a- and b-wave amplitudes corresponding with more extensive detachments at 0.01 cd·s/m² (a and b), 0.50 cd·s/m² (c and d), and 3.0 cd·s/m² (e and f) flash intensities. Open circles depict individual data points; horizontal lines depict medians (a–f).

Figure 6

Dichotomizing study eyes based on the extent of retinal detachment (i.e., ≤6 clock-hours or ≤50% detached (det) versus >6 clock-hours or >50% det) revealed a pattern of step-wise decline corresponding with more extensive detachments in the preoperative a- and b-wave amplitudes at 3.0 cd·s/m² flash intensity under 30 cd/m² background (bkgd) illumination (a and b) and in 30 Hz flicker responses (c). Open circles depict individual data points; horizontal lines depict medians (a–c).