Density of the Retinal Blood Flow and Thickness Mapping by Spectralis OCT in Patients with Fabry Disease

Abstract

Purpose : Fabry disease (FD) is an X-linked, inherited disorder caused by a deficiency of α-galactosidase A, with progressive accumulation of glycosphingolipids within several tissues and organs including the eye as well as vascular endothelium.In FD, macular assessment and density of the retinal blood flow have never been previously described.The aim of the study ist to investigate macular structure, retinal microvasculature and to explore a possible retinal biomarker of FD.

Methods : Pilot study of 20 eyes (10 patients) with molecular genetically confirmed FD and 20 eyes of 10 healthy controls.SD-OCT images (49 scans, 6x6mm) and OCT Angiography (OCTA) images 3x3mm were obtained using Spectralis OCT2 (Heidelberg Engineering GmbH,Germany).We measured total retinal thickness and 9 individual retinal layers in 9 macular sectors (ETDRS grid: 1.3 and 6 mm diameter) using software Verison 6.7.12.Thickness data are presented as mean value in μm (95% reference range) [range]. Superficial, deep and choriocapillaris flow density was measured using EyeProLabs® software.Results of 5 parafoveal sectors (central, superior, temporal, inferior, nasal) are presented as mean percentage (95% reference range) [range].Mean difference between groups was tested using nonparametric Mann Whitney U test. (SPSS Version 20, Inc.)

Results : Mean total retinal thickness in FD patients was 314.8 (309.1-320.7) [294.7-332.8] and 304.9 (299.3-310.6) [283.1-322.2] in controls (p=0.02). Extended results of each layer thickness and sub-analysis of each sector are displayed in Table 1.Mean superficial, deep and choriocapillaris flow density of all sectors in FD patients were decreased compared to healthy controls 37.9(33.1-42.7)[13.7-51.4]; 31.9(27.1-36.8)[5.2-46.7]; 42.5(37.7-47.4)[18.1-62.7] vs. 47.0(45.7-48.2 )[42.1-51.1]; 41.6(40.1-43.2) [35.6-47.4]; 61.1 (56.1-66.1)[44.1 -84.7] respectively.Flow density of all three layers was significantly lower in all sectors (p<0.01) except for the superficial layer in the central sector (p=0.06).

Conclusions : Macular thickness in FD patients was slightly higher than in healthy subjects.Decreased flow density in FD patients could suggest possible alterations in retinal microcirculation.The relevance of these findings warrants further study.OCTA may be clinically useful to evaluate retinal microvasculature in FD focusing on identification of new biomarkers and exploring their clinical relevance.

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