Supernormal flicker ERG with postoperative CME after nDSAEK in bullous keratopathy

PURPOSE: To report a case of supernormal electroretinogram (ERG) observed after non-Descemet stripping automated endothelial keratoplasty (nDSAEK) in a patient with bullous keratopathy, monitored longitudinally with flicker ERG and OCT. METHODS: A woman in her 70s underwent nDSAEK for bullous keratopathy. Postoperative retinal function was evaluated serially using full-field flicker ERG recorded with the RETeval system, together with macular OCT when feasible. RESULTS: On postoperative day 4, flicker ERG in the operated eye showed a prolonged implicit time (34.4 ms vs. 31.9 ms) and a markedly increased amplitude (31.4 μV vs. 19.2 μV) compared with the fellow eye. Macular OCT could not be obtained at that time. At the 3-week postoperative visit, OCT revealed cystoid macular edema (CME), and the flicker ERG amplitude was further increased with a slightly shorter implicit time. With topical nepafenac, CME gradually regressed and resolved by 1 year, accompanied by improvement in best-corrected visual acuity to 1.0; the flicker ERG amplitude and implicit time returned to levels comparable to those of the fellow eye. CONCLUSIONS: This case illustrates that transiently increased ERG amplitude accompanied by subtle prolongation of implicit time may occur following nDSAEK and could be associated with postoperative intraocular inflammation and CME. Serial RETeval-based flicker ERG may be useful for monitoring perioperative inflammatory responses after endothelial keratoplasty.