In vivo Visualization of Photoreceptor Layer and Lipofuscin Accumulation in Stargardt's Disease / Fundus Flavimaculatus by High Definition Optical Coherence Tomography

Abstract Purpose:To assess photoreceptor (PR) morphology in patients with Stargardt’s disease (STGD) and fundus flavimaculatus (FFM) using high definition optical coherence tomography (HD-OCT, OCT 4000 Cirrus, Humphrey-Zeiss, San Leandro, California). Methods:This was a prospective observational case series. Eight consecutive patients with STGD and FFM were prospectively examined by HD-OCT, a high-speed OCT system using spectral/Fourier domain detection, with an axial image resolution of 5 µm. Results:A total of 15 eyes were included in the study. HD-OCT was capable of visualizing regions of transverse PR loss in the foveal region. Moreover, we observed hyperreflective deposits which we classified in two types: type 1 lesions located in the inner part of the retinal pigment epithelium layer and type 2 lesions located at the level of the outer nuclear layer. Presence of type 1 lesion alone was associated with absence of complete loss of the PR layer in the foveal region in all eyes; presence of type 2 lesion was always associated with presence of type 1 lesions, and often (4/6 eyes) associated with complete loss of the PR layer within the foveal region. In addition, BCVA impairment showed a statistically significant correlation to the presence of complete loss of the PR layer in the foveal region (p=.0001), as well as to presence of type 2 flecks (p=.03). Conclusions:The possibility of in vivo visualization of the PR layer and of hyperreflective deposits in STGD/FFM might yield insight into genotypic/ phenotypic correlation, disease progression, and possibly treatment monitoring.