Characterisation of microvascular abnormalities using OCT angiography in patients with biallelic variants in <i>USH2A</i> and <i>MYO7A</i>.

Abstract

Using optical coherence tomography angiography (OCTA) to characterise microvascular changes in the retinal plexuses and choriocapillaris (CC) of patients with <i>MYO7A</i> and <i>USH2A</i> mutations and correlate with genotype, retinal structure and function. Twenty-seven patients with molecularly confirmed <i>USH2A</i> (n=21) and <i>MYO7A</i> (n=6) mutations underwent macular 6×6 mm OCTA using the AngioVue. Heidelberg spectral-domain OCT scans and MAIA microperimetry were also performed, the preserved ellipsoid zone (EZ) band width and mean macular sensitivity (MS) were recorded. OCTA of the inner retina, superficial capillary plexus (SCP), deep capillary plexus (DCP) and CC were analysed. Vessel density (VD) was calculated from the <i>en face</i> OCT angiograms of retinal circulation. Forty-eight eyes with either <i>USH2A</i> (n=37, mean age: 34.4±12.2 years) or <i>MYO7A</i> (n=11, mean age: 37.1±12.4 years), and 35 eyes from 18 age-matched healthy participants were included. VD was significantly decreased in the retinal circulation of patients with <i>USH2A</i> and <i>MYO7A</i> mutations compared with controls (p<0.001). Changes were observed in both the SCP and DCP, but no differences in retinal perfusion were detected between <i>USH2A</i> and <i>MYO7A</i> groups. No vascular defects were detected in CC of the <i>USH2A</i> group, but peripheral defects were detected in older <i>MYO7A</i> patients from the fourth decade of life. VD in the DCP showed strong association with MS and EZ width (Spearman's <i>rho</i> =0.64 and 0.59, respectively, p<0.001). OCTA was able to detect similar retinal microvascular changes in patients with <i>USH2A</i> and <i>MYO7A</i> mutations. The CC was generally affected in <i>MYO7A</i> mutations. OCT angiography may further enhance our understanding of inherited eye diseases and their phenotype-genotype associations.