Functional Evaluation of Retinal Pigment Epithelium and Outer Retinal Atrophy by High-Density Targeted Microperimetry Testing

Purpose: Complete retinal pigment epithelium (RPE) and outer retinal atrophy (cRORA) on OCT imaging has recently been proposed to describe end-stage atrophy in age-related macular degeneration (AMD) by international consensus and expected to be associated with a dense scotoma, but such functional evidence is lacking. This study sought to examine the visual sensitivity defects associated with cRORA and to determine OCT features associated with deep defects. Design: Observational study.Participants: Sixty eyes from 53 participants, including 342 microperimetry tests over 171 study visits.Methods: Participants underwent targeted high-density threshold-based microperimetry testing of atrophic lesions (with at least incomplete RPE and outer retinal atrophy [iRORA]) with a 3.5(degrees )diameter grid. The maximum extent of signs of atrophy for all lesions was graded on OCT imaging.Main Outcome Measures: Number of deep visual sensitivity defects (threshold < 10 decibels [dB]).Results: Presence of choroidal signal hypertransmission > 500 mu m, complete RPE loss >250 mu m, and inner nuclear layer and outer plexiform layer subsidence, and hyporeflective wedge-shaped band (defined as nascent geographic atrophy [nGA]) > 500 mu m (P < 0.020), but not RPE attenuation or disruption (P > 0.192), were all independently associated with a significant increase in the number of deep visual sensitivity defects < 10 dB. Only cRORA lesions with hypertransmission > 500 mu m or complete RPE loss > 250 mu m, or with both of these features (P < 0.001), but not lesions with only hypertransmission 250-499 mu m (P = 0.303), had significantly more deep visual sensitivity defects < 10 dB compared with iRORA lesions. Lesions with nGA > 500 mu m, irrespective of the presence of hypertransmission > 500 mu m and/or complete RPE loss > 250 mu m, also showed a higher number of deep visual sensitivity defects < 10 dB compared with lesions without nGA > 500 mu m (P < 0.011). Conclusions: Not all cRORA lesions show a difference in the number of deep visual sensitivity defects compared with iRORA. Instead, hypertransmission > 500 mu m, complete RPE loss > 250 mu m, and nGA > 500 mu m are all OCT features independently associated with deep visual sensitivity detects that could help inform the definition of end-stage atrophy on OCT imaging.Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.(c) 2023 by the American Academy of Ophthalmology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).