Foveal avascular zone morphology and parafoveal capillary perfusion in sickle cell retinopathy

Abstract

Background/aimsTo assess foveal avascular zone (FAZ) morphology and parafoveal capillary perfusion in patients with various stages of sickle cell retinopathy (SCR) using optical coherence tomography angiography (OCT-A).MethodsThis is a multi-institutional retrospective study of patients with various stages of SCR compared with healthy controls. Parafoveal OCT-A images obtained using a commercial spectral domain-OCT system were reviewed. Foveal-centred 3×3 mm full vascular slab OCT-As were used for image processing and data analysis. FAZ area, perimeter, and acircularity index were determined on the OCT-A image after manual delineation of the FAZ border. Quadrant-based parafoveal capillary density and per cent area deviating from normal distribution were also measured.ResultsFifty-two patients with SCR (33 non-proliferative and 19 proliferative) and 20 age and race-matched healthy controls were included. One randomly selected eye per study participant was analysed. FAZ perimeter and acircularity index were significantly greater in SCR eyes when compared with the controls. While parafoveal capillary density was significantly lower, per cent area deviated from normal distribution was significantly higher in SCR eyes than that of the control. However, no statistically significant difference between the two SCR stages was observed. In quadrant-based analysis, the temporal quadrant showed greater parafoveal capillary dropout due to SCR, with the most profound effect in patients with proliferative SCR.ConclusionsAbnormal FAZ morphology and altered parafoveal capillary perfusion were found in patients with SCR. Our customised OCT-A image analysis method uniquely highlights significant quantitative alterations in perfusion density mapping in a qualitative display, with minimal obscuration of OCT-A image detail.

Analysis of the foveal microvasculature in sickle cell disease using swept-source optical coherence tomography angiography

“…This suggests that the mechanisms involved in the peripheral SCDR and in the macular alterations are different. Moreover, we did not find any association between macular vascular density and peripheral non perfusion unlike in vein occlusions 29 , confirming previous results 30 . We can assume that no difference between genotypes is observed, since the DCP, mainly involved in SCD maculopathy, is composed only by vein 31 .…”

Sickle Cell Maculopathy: Prevalence, Associations and Impact on Visual Acuity

“…1). Similarly, Lynch et al [23]reported foveal avascular zone and parafoveal capillary density abnormalities in eyes with sickle cell retinopathy compared to controls. As reported by others, the structural OCT abnormalities in the patients in this series were most evident in the temporal quadrant.…”

The effect of treatment on retinal microvasculature in children with unilateral amblyopia

“…16 Currently, it is measured to quantify the disruption of the terminal capillary ring at the fovea; it has been shown to be associated with disease progression in vascular maculopathy. 11,12,17 Reduced FAZ circularity in the amblyopic eyes indicates a more irregular FAZ shape in comparison with that of the fellow eyes, showing unequal interocular development of the macular vascular network. Our results are consistent with a population-based nested case-control study of 30 children with amblyopia and 1,045 controls conducted by Wong and colleagues, 18 who reported a reduced FAZ circularity (measured by OCTA) in strabismic and anisometropic amblyopic eyes relative to control eyes.…”