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High myopia (HM) is a well-recognized risk factor for the development of glaucoma, with myopic eyes showing a higher susceptibility to glaucomatous damage compared with non-myopic eyes. However, diagnosing glaucoma in highly myopic individuals remains challenging due to atypical optic disc features, such as peripapillary atrophy, disc tilt and abnormal disc sizes, which may mimic glaucomatous damage.[1, 2] Ruan et al. used swept-source optical coherence tomography angiography (SS-OCTA) to assess the diagnostic efficacy of microvascular dropout (MvD) in detecting glaucoma in highly myopic eyes. This technology enabled visualization of MvD not only in the peripapillary area (MvD-P), but also within the optic disc (MvD-D), primarily localized to the lamina cribrosa (LC), the initial site of glaucomatous damage.[3]
This prospective cross-sectional study included 107 participants divided into a high myopia (HM) group and a high myopia with glaucoma (HMG) group. MvD-D outperformed all other structural (RNFL, GCIPL) and vascular metrics (macular and optic nerve head vessel density, and MvD-P), achieving the highest area under the curve of 0.95. MvD-D was identified in 91% of HMG patients but only 18% of HM patients. It was independently associated with visual field loss (β=−0.42, p=0.02), although it reached a floor effect at MD <−15 dB, suggesting it is more sensitive for monitoring early to moderate glaucoma. Study limitations include the cross-sectional design and limited generalizability due to enrollment from a single center of young patients with high myopia. The results require confirmation in larger multicenter cohorts that include diverse racial groups and older patients. Furthermore, variability in OCTA measurements and challenges in assessing MvD-D in highly myopic eyes, particularly those with small optic discs and thick neuroretinal rims, should be considered.[4] In summary, MvD-D detected by OCTA represents a novel and highly specific marker for glaucoma in highly myopic eyes, demonstrating potential as both a diagnostic and prognostic tool in clinical practice.