NATURAL COURSE OF AGE-RELATED RETENTIONAL AVASCULAR PIGMENT EPITHELIAL DETACHMENT: Support For The Lipid Barrier Hypothesis.

Purpose: Retentional pigment epithelial detachment (PED) associated with age-related scattered hypofluorescent spots on late-phase indocyanine green angiography (ASHS-LIA) is hypothesized to be caused by Bruch membrane's lipid barrier. This study aimed to report the natural course of retentional PED and evaluate the relationship between retentional PED evolution and ASHS-LIA.

Methods: Patients with treatment-naïve retentional PED were enrolled and observed every 3 months for at least 12 months. Treatment was not performed except for secondary macular neovascularization.

Results: In 55 studied eyes with a median follow-up of 18.0 (range: 12-36) months, 87.3% (48/55) of the retentional PEDs persisted, 7.3% (4/55) resolved, and 5.5% (3/55) progressed to polypoidal choroidal vasculopathy. The mean PED area significantly increased during the follow-up ( P < 0.001) and with the ASHS-LIA grade at each follow-up point (all P <0.05), especially during the first 6 months before approaching the edge of confluent ASHS-LIA. Persistent PEDs were mostly stable (52.1%) or enlarged (45.8%) but reduced in only 1 case (2.1%) because of retinal pigment epithelium microrip at the edge of PED. The persistent PEDs were all within the ASHS-LIA region, especially the macular confluence region. The resolved PEDs all had grade 1 ASHS-LIA and resolved after gradual expansion of PED beyond the confluent ASHS-LIA region. Pigment epithelial detachments that progressed to macular neovascularization all had confluent grade 2 or 3 ASHS-LIA. Retinal pigment epithelium microrips or apertures within PED did not affect the progression of the PED.

Conclusion: The natural course of retentional PED is closely related to the features of ASHS-LIA and supports its lipid-barrier hypothesis.