Adaptive Optics imaging in patients affected by Pseudoxanthoma Elasticum

Abstract Purpose To describe the retinal findings of patients affected by Pseudoxanthoma Elasticum (PXE) using a multimodal imaging approach including flood-illumination adaptive optics ophthalmoscopy (AO). Design Retrospective case series Materials and methods Patients affected by PXE were retrospectively studied. Clinical data, color, infrared and autofluorescence fundus imaging, OCT scans and AO examinations were collected. Furthermore, the photoreceptor count was assessed. PXE diagnosis was confirmed by a positive skin biopsy and/or genetic testing. Results Twenty-one eyes of 18 patients (11 females and 7 males) were included in the study. In 3 patients, both eyes were studied. The mean age at examination was 37 ± 16.4 years (range 11-66) and the mean best-corrected visual acuity (BCVA) was 0.1 ± 0.2 LogMAR (range 0-1). We identified 3 types of angioid streaks (AS) using AO: “crack”, “band” and “hypopigmented”. The first 2 were very similar and they differed in size; the third type showed specific clinical features. Comet lesions appeared as hyper-reflective round lesions on AO imaging. In all eyes the cone mosaic appeared reduced inside the streaks compared to the neighboring areas (13532.8 ± 1366.5 cones/mm2 vs 16817.1 ± 1263.0 cones/mm2 respectively). Conclusion Using AO imaging in PXE-related retinopathy we were able to observe the presence of the photoreceptors within the angioid streaks, differentiate 3 types of angioid streaks, based on size and reflective features, and identify the very small crystalline bodies not identifiable using other retinal imaging techniques.