Blind patients in end-stage inherited retinal degeneration: multimodal imaging of candidates for artificial retinal prosthesis.

PURPOSE To characterize the imaging features of blind patients with end-stage inherited retinal degeneration (IRD) and to assess possible morpho-functional correlations. METHODS In this observational cross-sectional study, we reviewed the clinical data and multimodal imaging of 40 eyes of 21 blind (light perception or less) institutional patients affected by end-stage IRD screened for Alpha AMS (Retina Implant AG, Reutlingen, Germany) retinal prosthesis eligibility. Analysis was carried out using spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography and fundus autofluorescence. RESULTS Among patients with IRD-related low vision, the extrapolated prevalence of the blind was roughly 10%, median age 60.4 years with a disease duration of 40.4 years, showing epiretinal membranes (80%), hyperreflective intraretinal nodules (90%) and the absence of the ellipsoid zone (77.5%) on SD-OCT examination. Cystoid macular oedema was present in 52.5% of eyes, the majority of which being of the microcystoid subtype (42.5%), while 37.5% of eyes also lacked outer and inner retinal layer segmentation. Disease duration was found to be predictive of disrupted retinal layers (P = 0.029) and microcystoid macular oedema (P = 0.035), which was also more frequent in eyes without light perception (P = 0.013). CONCLUSIONS Eyes without vision due to end-stage IRD have a typical imaging pattern, predominantly characterized by epiretinal membranes, hyperreflective intraretinal nodules and the absence of the ellipsoid zone. Furthermore, microcystoid macular oedema and retinal layer disruption may be considered as signs of longstanding disease.