Evolution of outer retinal folds occurring after vitrectomy for retinal detachment repair

Purpose.: To assess the evolution of outer retinal folds (ORFs) occurring after repair of rhegmatogenous retinal detachment (RRD) using spectral domain-optical coherence tomography (sd-OCT) and fundus autofluorescence (FAF), and to discuss their pathogenesis. Methods.: Twenty patients were operated on with 25-gauge pars plana vitrectomy and 20% sulfur hexafluoride gas injection for primary macula-off RRD repair and were followed prospectively. Sd-OCT and FAF images were recorded at 1, 3 and 6 months postoperatively. Results.: ORFs appeared on sd-OCT as hyperreflective lesions consisting of folded inner segment/outer segment of photoreceptors band and external limiting membrane band. Corresponding lines of increased or decreased autofluorescence were observed on FAF. Over the follow-up, the thick hypoautofluorescent lines progressively evolved to thick hyperautofluorescent lines and to thin hyperautofluorescent lines and eventually disappeared. Concomitantly, OCT scans revealed that the corresponding hyperreflective lesions decreased in number, height, and size. In six cases FAF assessment at month 6 was precluded by cataract development. Conclusions.: ORFs tend to resolve spontaneously within a few months from operation leaving no or subtle abnormalities at the level of the outer retinal layers. OCT is superior to FAF to follow the evolution of ORFs in phakic eyes. The following factors might be involved in ORFs pathogenesis: structural changes occurring in the detached retina, residual pockets of subretinal fluid after retinal reattachment, intravitreal gas, unintentional retinal translocation, and intraoperative or perioperative hypotony