Longitudinal analysis of microvascular changes in sickle cell disease using swept-source optical coherence tomography angiography

Abstract

Purpose: To analyze the changes in macular vascular densities (VD) and foveal avascular zone (FAZ) over a 6-year period using swept-source optical coherence tomography angiography (OCTA) in sickle cell patients compared to unaffected controls. Methods: Thirty eyes of sickle cell patients and 12 eyes of unaffected controls matched for age and ethnicity were examined at a 6-year interval using the same imaging protocol, including ultra-wide-field angiography, swept-source OCT and 3x3mm OCTA. The macular VD and FAZ were measured on ImageJ software according to previously reported algorithms. Results: In sickle cell eyes, the mean FAZ significantly increased (p <0.01), and the VD decreased in the foveal (within a circle of 1.5 mm in diameter around the foveal center) and temporal areas in both the superficial and deep capillary plexuses (p <0.01). The VD did not change over time in the parafoveal area (annulus between two circles of 1.5 and 3 mm in diameter) and in the superior, inferior, and nasal sectors. No worsening of peripheral retinopathy was observed in the cohort during the follow-up, except for one eye that developed sea-fan. In the control eyes, no microvascular change was observed over time in terms of FAZ size and VD. Conclusion: These longitudinal OCTA findings in sickle cell patients showed an enlargement of the FAZ and a decrease in VD in the temporal and perifoveal regions despite the absence of progression of peripheral retinopathy, suggesting a worsening of the macular non-perfusion over time in sickle cell disease.