Optical Coherence Tomography Angiography in Fabry disease

Abstract

Purpose : Fabry Disease (FD) is an X linked lysosomal storage disorder characterized by deficient activity of the enzyme α galactosidase A with subsequent pancellular accumulation of sphingolipids. Retinal manifestations in FD identified to date are limited to vessel tortuosity. Our aim is to characterise the vasculature of the retina in patients with Fabry Disease (FD) by means of optical coherence tomography angiography (OCT-A).

Methods : Observational case-control study. Clinical and imaging data from patients with genetically proven FD were reviewed. A complete ophthalmological examination, including traditional B-scan OCT and OCT-A were carried out. We assessed vessel density of superficial capillary plexus (SPVD, mm²), deep capillary plexus (DPVD, mm²), the foveal avascular zone area of the superficial capillary plexus (SPFAZ, mm²) and of the deep capillary plexus (DPFAZ, mm²). The presence of vascular tortuosity and aneurysmatic vessels dilation and potential links with quantitative parameters were assessed. OCTA-scans were compared to those obtained from age-matched healthy controls.

Results : Thirteen patients (M:F=4:9) (26 eyes) were included (FD-group). The mean age was 51.2 years (±14.9). The mean Best Corrected Visual Acuity (BCVA) was 0.1 LogMar (± 0.05). At fundus examination retinal vessel tortuosity was found in 14 eyes (53.8%). In the FD-group the mean SPVD was 1.55 ± 0.35 mm², the mean DPVD was 3.05 ± 0.53 mm², the mean SPFAZ was 0.24 ± 0.08 mm² and the mean DPFAZ was 0.30 ± 0.07 mm². In the control group the mean SPVD was 1.62 ± 0.24 mm², the mean DPVD was 3.32 ± 0.23 mm², the mean SPFAZ was 0.32 ± 0.10 mm² and the mean DPFAZ was 0.38 ± 0.13 mm². There was a statistically significant reduction in the DPVD in the FD-group compared to controls (p<0.001). There was a statistically significant reduction in both DPFAZ and SPFAZ in FD group (p<0.001) compared to controls.

Conclusions : In our study, we evaluated for the first time in FD the chorioretinal vasculature by means of OCT angiography, a rapid and non-invasive procedure. OCT-A allowed the specific and separate evaluation of the various vascular layers, obtaining significant quantitative parameters. Vascular density reduction in the deep capillary plexus, if confirmed in further investigations, could be clinically significant for the diagnosis and follow-up of FD patients.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.