Outer Retinal Corrugations in Rhegmatogenous Retinal Detachment: The Retinal Pigment Epithelium-Photoreceptor Dysregulation Theory

center dot PURPOSE: Outer retinal folds occur when outer reti-nal corrugations (ORCs) persist after retinal reattach-ment with worse functional outcomes. We investigate the pathophysiology of ORCs in vivo. center dot DESIGN: Prospective cohort study. center dot METHODS: Patients with rhegmatogenous retinal de-tachment (RRD) presenting to St. Michael's Hospital, Toronto, Ontario, Canada, between August 2020 and February 2022 were assessed with swept-source opti-cal coherence tomography (SS-OCT) and ultra-widefield SS-OCT for ORCs. Clinical characteristics of eyes with/without ORCs were compared. Mathematical mod-els were used to deduce mechanical properties leading to ORCs. center dot RESULTS: Sixty-six patients were included. More than half (60.6%, 40/66) were fovea-off and 48.4% (32/66) had ORCs at presentation. All eyes (32/32) with ORCs had retinal pigment epithelium (RPE)-photoreceptor dysregulation for at least 2 days, defined as loss of RPE control with acute, progressive, and extensive RRDs. In all (34/34) eyes without ORCs the RPE was in rela-tive control of the subretinal space with nonprogressive subclinical or small localized or resolving RRDs, or with RPE-photoreceptor dysregulation for fewer than 2 days. Mathematical models indicate that a modulus of elasticity of the outer retina relative to the inner retina of 0.05 to 0.5 leads to ORCs.center dot CONCLUSIONS: ORCs develop with (1) acute exposure of subretinal space to liquified vitreous, (2) for > 2 days, that (3) overwhelms RPE capacity, leading to progressive and extensive RRD. Mathematical models suggest that a reduction in the modulus of elasticity of the outer retina occurs such that intrinsic compressive forces, likely re-lated to progressive outer retinal hydration and lateral ex-pansion, lead to ORCs. Understanding the pathophysiol-ogy of ORCs has implications for management. (Am J Ophthalmol 2023;245: 14-24. (c) 2022 Elsevier Inc. All rights reserved.)