Purpose To quantify retinal and choriocapillaris (CC) microvasculature in highly myopic (HM) eyes with myopic macular degeneration (MMD) using swept-source optical coherence tomography angiography (SS-OCTA).
Methods 162 HM eyes (spherical equivalent ≤ −6.0 dioptres or axial length (AL) ≥26.5 mm) from 98 participants were enrolled, including 60 eyes (37.0%) with tessellated fundus, 54 eyes (33.3%) with peripapillary diffuse chorioretinal atrophy (PDCA), 27 eyes (16.7%) with macular diffuse chorioretinal atrophy (MDCA) and 21 eyes (13.0%) with patchy or macular atrophy. PLEX Elite 9000 SS-OCTA was performed to obtain perfusion densities (PD) of the superficial and deep retinal capillary plexus, and CC signal voids (number, area and density).
Results Retinal PD decreased with increasing severity of MMD. Multivariable analysis showed that after adjustment of age and other factors, retinal PD decreased significantly in eyes with longer AL (β≤−0.51, p<0.001) and with an MMD severity of MDCA or worse (β≤−1.63, p<0.001). Reduced retinal PD were significantly associated with worse vision (β≤−0.01, p≤0.04). In terms of CC signal voids, multivariable analysis showed that longer AL (p<0.001), but not MMD severity (p≥0.12) was significantly associated with CC signal void changes in the earliest stage of MMD.
Conclusion We demonstrate significant OCTA alterations in the retina and CC in HM eyes with varying severities of MMD. In eyes with early-stage PDCA, lower retinal PD and more extensive CC signal voids are predominantly associated with increasing AL. In contrast, in eyes with MDCA or worse, MMD itself was associated with sparser retinal and CC circulation.
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CWW and QVH contributed equally.
Presented at This work was presented, in part, at the 2020 Macula Society Annual Meeting, San Diego, California.
Contributors FZ is the first author doing data analysis and writing the manuscript; JC supervised research rationals and manuscript writing; BT and MK performed image processing; MY assisted in statistics; QH helped with image quality check and extraction; CMGC, MA, SYL and the Retinal Group of SNEC conducted patient recruitment; TYW gave guidance on the study; LS gave guidance on the study and kindly offered the OCTA machine from his research funding; CWW and QVH are the PI of the study and contributed equally. All coauthors contributed to the writing of the manuscript.
Funding This work was supported in part by the Singhealth-Duke-NUS Eye Academic Clinical Programme Nurturing Clinician Scientist Scheme (NCSS/R1364/50/2016, CWW, Singapore, CG/C010A/2017; OFIRG/0048/2017; OFLCG/004c/2018; and TA/MOH-000249-00/2018), National Eye Institute/NIH K08 Grant (1 K08 EY023595, QVH, USA) and the National Medical Research Council (grant CSA-MOH-000151, QVH, Singapore).
Disclaimer The funding organisations had no role in the design or conduct of this research.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval This study was approved by the SingHealth Centralised Institutional Review Board, Singapore (protocol number R1364/50/2016) and conducted in accordance with the Declaration of Helsinki.
Data availability statement Data are available on reasonable request. High-resolution digital photographs and OCTA imagings were stored on the Singapore Eye Research Institute server. The corresponding author has full access to all the data in the study.
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