Aims To describe the vascular abnormalities in patients affected by Stargardt disease (STGD1) by means of optical coherence tomography angiography (OCT-A).

Methods Cross-sectional case series, with the following inclusion criteria: diagnosis of STGD1, clear ocular media, and stable fixation. Patients underwent best-corrected visual acuity (BCVA), biomicroscopy, applanation tonometry, short-wavelength fundus autofluorescence (SW-FAF) (HRA Heidelberg, Germany), 3×3 Swept Source OCT-A (Topcon Corporation, Japan). Foveal avascular zone (FAZ) area was manually outlined and removed from the vessel density analysis (ImageJ). Main outcome was vessel density assessment in the superficial capillary plexus (SCP), in the deep capillary plexus (DCP), and in the choriocapillaris (CC) of patients with STGD1.

Results Nineteen patients (36 eyes) were recruited for the study (10 females, 52.6%). Mean age was 33±5.7 years and mean BCVA was 0.6±0.3 logarithm of the minimum angle of resolution. Thirty-six healthy age-matched subjects (one eye for each patient) acted as a control group. Qualitative analysis of OCT-A revealed areas of reduced vascular density in superficial and DCPs. CC showed focal defects partially corresponding to the flecks on SW-FAF imaging. Quantitative analysis of OCT-A disclosed a statistically significant difference in the density of the SCP (0.302±0.062 vs 0.365±0.042; p=0.0002) and the DCP (0.303±0.081 vs 0.399±0.045; p<0.001) compared with controls. To analyse CC, patients with STGD1 were divided into two groups, according to the presence of chorioretinal atrophy. Patients with atrophy showed significantly lower CC density compared with controls (p=0.0003) and patients without atrophy (p=0.001). Patients with STGD1 showed a larger FAZ at the SCP level compared with controls (p=0.012).

Conclusions Vascular impairment in patients affected by STGD1 is concentrated in superficial and the deep retinal plexuses. Patients with atrophic changes have a greater reduction in CC density compared with controls (‘dark atrophy’). Morphological vascular evaluation may become an important step for predicting STGD1 treatment outcomes.