Ocular Blood Flow in Eyes with Myopia and Glaucoma: From Pathophysiology to Clinical Implications
Naoki Takahashi, Naoki Kiyota, Akiko Hanyuda, Satoru Tsuda, Toru NakazawaThe global prevalence of myopia is increasing, and the combination of myopia and glaucoma is widely expected to become an important clinical and public health issue. Myopic eyes undergo axial elongation and posterior pole remodeling, leading to optic disc tilt, peripapillary deformation, choroidal thinning, and altered spatial relationships between the optic nerve head and its vascular supply. Glaucomatous optic neuropathy is associated with retinal ganglion cell damage, lamina cribrosa deformation, and ocular blood flow impairment. Recent advances in optical coherence tomography angiography and laser speckle flowgraphy have enabled noninvasive assessment of retinal, peripapillary, choroidal, and optic nerve head circulation. These modalities have revealed reduced radial peripapillary capillary density, choroidal microvasculature dropout, and reduced optic nerve head tissue blood-flow signal in glaucomatous eyes. In eyes with myopia and glaucoma, myopia-related structural deformation and glaucoma-associated perfusion abnormalities may coexist and show sectoral correspondence with neural damage, particularly in regions related to the central visual field. This review summarizes the anatomical background of ocular blood flow, myopia-induced structural and vascular changes, glaucoma-associated blood flow impairment, and their interaction in eyes with myopia and glaucoma. Potential therapeutic approaches targeting ocular blood flow are also discussed, although evidence beyond intraocular pressure reduction remains limited.