Background/aims To 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).
Methods This 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.
Results Fifty-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.
Conclusions Abnormal 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.
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Correction notice The paper has been corrected since it was published Online First. Table 2 has been replaced with an updated version.
Contributors AWS and TYC were involved in study conceptualisation and supervision. All authors were involved in data curation, data interpretation, manuscript drafting and editing. GL and TYC were involved in formal data analysis and validation.
Funding This study was supported by the National Eye Institute of the National Institutes of Health under award numbers R01EY027301 and R01EY024969. Additional funding for this research was provided by the New York Eye and Ear Infirmary Foundation Grant, Marrus Family Foundation, the Geraldine Violett Foundation, the Edward N & Della L Thome Memorial Foundation, the Jorge N Buxton Microsurgical Foundation, unrestricted contributions to the Johns Hopkins University Retina Division research fund and by private philanthropy from Gail C and Howard Woolley, Baltimore, Maryland.
Disclaimer The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The sponsors and funding organisations had no role in the design or conduct of this research.
Competing interests RBR: Optovue: Code C (Consultant); Boehringer Ingelheim: Code C (Consultant); Astellas: Code C; Genentech-Roche: Code C; NanoRetina: Code C; OD-OS: Code C; Opticology: Code I (Personal Financial Interest); Guardion: Code I (Personal Financial Interest); GlaucoHealth: Code I (Personal Financial Interest); Regeneron: Code C; Bayer: Code C; Diopsys: Code C (Consultant); Teva: Code C (Consultant). JC: Optovue: Code F (Financial Support). REL: Optovue: Code C (Consultant).
Patient consent for publication Not required.
Ethics approval Johns Hopkins University School of Medicine Institutional Review Board
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.
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