Abstract
Purpose :
Ischemic microangiopathy is well known in sickle cell disease (SCD) using fluorescein angiography. We performed a prospective observational clinical study, to assess the size of foveal avascular zone (FAZ) and explore the perifoveal microvasculature changes in the superficial (SCP) and deep capillary plexi (DCP), using optical coherence tomography angiography (OCT-A).
Methods :
We included in a prospective study all consecutive patients with electrophoretic confirmation of SCD. OCTA swept source scans (Triton Plus, Topcon, Tokyo, Japan) with a scanning area of 3 x 3 mm, and an ultra wide field (UWF) retinography (California, Optos, Fife, Scotland) were recorded for all patients. For OCTA analysis, preset parameters were used to segment the SCP and DCP. The size of the FAZ in SCP and DCP was manually measured by 2 independent examiners. The number of vascular branching points was automatically assessed based on the vascular skeletonization with Image J software. Eyes were staged based on the Goldberg classification of SCD retinopathy using ultra-wide field imaging (UWF). Our primary endpoint was to compare the FAZ size in SCD patients (HbSS and HbSC) to control. Our secondary endpoints were the number of branching points, the central retinal thickness (CRT), and the Golberg classification compared between all groups.
Results :
46 eyes of 24 consecutive patients were included in HbSS genotype group (n=27), in HbSC genotype group (n=19) and 15 eyes of 8 healthy subjects in a control group. The FAZ measured in the DCP was significantly larger in both HbSC (p= 0.0001) and HbSS (p=0.0004) group compared to control. There was no significant difference for FAZ size in the SCP, for CRT, and for number of superficial vascular branching points between both genotypes. There was less branching points in HbSC (p=0.034) and HbSS (p=0.0014) than in the control group. The Goldberg stage was significantly higher in the HbSC than in the HbSS group (2.21 vs 1.22, p = 0.0062), and no other significant difference was found between SCD groups.
Conclusions :
OCTA provides useful information about macular microvasculature and structural alterations associated in SCD retinopathy. Ischemic abnormalities seem to be more predominant in the DCP in case of SCD retinopathy.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.