Atypical retinal pigment epithelial defects with retained photoreceptor layers: a so far disregarded finding in age related macular degeneration

Abstract

Background: To report patients with age-related macular degeneration and atypical central retinal pigment epithelium (RPE) defects not attributable to geographic atrophy (GA) or RPE-tears with overlying preserved photoreceptor layers.

Methods: Multimodal imaging case-series evaluating the course of atypical RPE- defects in patients with AMD using Color fundus images, Optical coherence tomography (OCT), OCT-Angiography, fundus autofluorescence (FAF) and fluorescein-angiography (FA).

Results: Ten patients were identified. Three patients had a prior RPE-rip and were excluded. Seven patients with a mean follow-up period of 47 ± 38 months after the occurrence of the RPE-defect were included (age range 71-87 years). Mean distance Best corrected visual acuity (BCVA) at initial presentation was 0.36 ± 0.29logMAR and at last follow-up visit 0.51 ± 0.43logMAR. Patients presented with clinically apparent GA on funduscopy and FAF, but preserved photoreceptor layers on optical coherence tomography (OCT). On FA there was early hyperfluorescence and late pooling visible. Over time, migration of RPE/drusenoid material right above the Bruch's membrane with concomitant decrease of hypoautofluorescence was detectable in 4 cases. An enlargement of the RPE-defect was apparent in the remaining 3 cases. The majority (n = 4) showed a drusenoid pigment epithelium detachment (PED) preceding the lesion.

Conclusions: Beside GA and characteristic RPE-tears, another atypical form of RPE-defect with overlying preserved photoreceptor layers are found in AMD. This so far disregarded subgroup of patients present with reasonable visual function and long-term survival of photoreceptors layers. Repair mechanisms such as ingrowth of RPE/drusenoid material and persistent subretinal fluid (SRF), but also a RPE-independent visual cycle for cone photopigment within the neurosensory retina may contribute to their favorable course.

Keywords: Age-related macular degeneration; Geographic atrophy; Photoreceptor; RPE tear; RPE-aperture.

Fig. 1

Top: 2010: Initial presentation with drusenoid pigment epithelium detachment (PED). 2011: spontaneous resolution of PED. 2013: Spontaneous RPE aperture. The OCT reveals an RPE defect with SRF. The overlying photoreceptors are intact. Fundus autofluorescence (FAF) and fluorescein angiography (FA) shows hypoautofluorescence and pooling corresponding to RPE defect, respectively. 2014 Resolution of SRF after anti-VEGF treatment. Intact ellipsoid zone and ELM directly attached to the Bruch’s membrane. Enhanced choroidal signaling due to the absence of RPE is evident. Some ingrowth of iso-autofluorescent material is already notable on FAF (red, bold arrow). Also SD-OCT reveal some hyperreflective material (thin, red arrow) 2015 Ingrowth and regeneration of RPE/drusenoid material with consecutive decrease of enhanced choroidal signaling (thin, red arrow), hypoautofluorescence (red, bold arrow) and window defect Red (thin and bold) arrows denote hyperreflective and hyperFAF material, suggestive of potential ingrowth of drusenoid/RPE material

Fig. 2

2010: A circumscribed RPE atrophy is noted on color fundus with corresponding window defects visible on FA. 2011: The now performed FAF and SD-OCT highlights the loss of RPE with corresponding hypo autofluorescence on FAF and enhanced choroidal signaling on SD-OCT. The ELM, ellipsoid zone and the interdigitation zone are attached to the Bruch’s membrane. 2012 and 2013: Decrease in window defect on FA, hypoautofluorescence on FAF and enhanced choroidal signaling on SD-OCT is noted. Ingrowth of RPE/drusenoid material (red, thin arrow) is evident overlaid by PR layers

Fig. 3

Initial presentation 2005 shows a large RPE atrophy on color fundus with corresponding hypoautofluorescence on FAF. A window defect with evidence of pooling within the subretinal space is visible on FA without a definite evidence of a CNV. 2007: Follow up images 2007 reveal a central RPE defect, SRF and a preserved photoreceptor (PR) layer. Obvious shedding of the PR-outer segments is evident. 2009: The RPE defect has increased in size, the SRF has persisted despite anti-VEGF therapy. The PR are present. 2015 Increase of the RPE defect, the overlying PR are still present but the lengths are reduced. The OCT angiography of the choriocapillaries confirms the absence of a CNV

Fig. 4

Depicts the presentation on OCT of each included patient