Comparative analysis of autofluorescence and OCT angiography in Stargardt disease

Aims To characterise the vasculature of the retina in patients with Stargardt disease (STGD) using optical coherence tomography angiography (OCTA) and to compare these functional findings with fundus autofluorescence (FAF) imaging. Methods This observational study included consecutive patients with STGD. The choriocapillaris (CC) layer was analysed on OCTA and retinal pigment epithelium (RPE) changes were assessed on FAF. Areas of CC and RPE impairment were quantified and correlated. Results Twenty-two patients suffering from different stages of STGD were enrolled. OCTA revealed a vascular rarefaction with vascular prominence in 15 (35%) eyes while the remaining cases had pure vascular rarefaction. On FAF imaging, 25 (58%) eyes had a peripapillary halo, a hypofluorescent lesion in foveal area and the presence of both hypofluorescent and hyperfluorescent changes. On FAF imaging, the average area of RPE impairment was 6.7 +/- 4.4 mm(2) while on OCTA a hypointense area of 4.2 +/- 3.6 mm(2) was shown at the level of the CC layer. Mann-Whitney U test showed a statistically significant difference in terms of lesion extension between these two findings (p=0.004). Conclusion RPE damage on FAF appears to be significantly larger than CC layer vessel loss on OCTA, which suggests that RPE damage might precede that of CC.