Abstract
Purpose :
To determine whether there is a difference in retinal thickness, vessel density and foveal avascular zone (FAZ) area in children with sickle cell disease when compared to age- and race-matched controls.
Methods :
In this prospective observational study, children with HbSS, HbSC, and HbS-Thal genotypes and their age- and race-matched controls were recruited from the Wilmer Eye Institute between January 2017 to November 2018. Measurements of total retinal thickness and volume, whole ETDRS superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density, and FAZ area were obtained using 3x3mm OCTA scans (AngioVue; Optovue Inc). Retinal thicknesses and volumes were analyzed for the inner (internal limiting membrane [ILM] to inner plexiform layer), middle (inner plexiform to outer plexiform layer), and total (ILM to Bruch’s membrane) retina. Using generalized linear mixed models adjusting for age and gender with random intercept for patient, these measurements were compared between sickle cell genotypes and controls.
Results :
A total of 32 HbSS eyes (17 patients), 22 HbSC eyes (11 patients), 12 HbS-Thal eyes (6 patients) and 18 control eyes (10 patients) were included. Inner, middle, and total retinal thicknesses and volumes (inner: thickness -10.7um; volume -0.10um3; middle: -6.0um, -0.05um3; total: -20.5um; -0.19um3) were decreased in HbS-Thal eyes when compared to control eyes (inner: 104.1um; 0.94um3; middle: 66.8um, 0.60um3; total: 308.5um; 2.78um3) (all p<0.05), but no difference in these measurements was observed for HbSS and HbSC eyes. Superficial and deep vessel densities were lower in HbSS (SCP -2.82%, DCP -4.18%), HbSC (SCP -4.67%, DCP -3.64%) and HbS-Thal (SCP -6.15%, DCP -3.77%) eyes when compared to controls (SCP 50.76%, DCP 50.64%) (all p<0.05). FAZ area was larger in HbSC eyes (+0.136mm2) when compared to controls (0.26 mm2) (p=0.036) but no difference was found between HbSS or HbS-Thal eyes and controls.
Conclusions :
Pediatric sickle cell disease patients possess lower vascular density compared to age- and race-matched controls. In addition, when compared to controls, HbS-Thal patients have thinner retinas, and HbSC patients have larger FAZ area. Further study is needed to characterize the differences in these measurements across various sickle cell genotypes.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.