High Myopia-Induced Optic Nerve Head Deformation and Glaucoma Progression: A Three-Year Follow-Up Study

Purpose: To investigate the biomechanical effects of high myopia (HM)-related optic nerve head (ONH) structural changes on glaucoma progression and identify key predictive parameters. Methods: This prospective cohort study enrolled 242 eyes: 97 highly myopic glaucoma (HMG), axial length > 26.5 mm; 145 open-angle glaucoma (OAG), axial length ≤ 26.5 mm. ONH parameters, including Bruch's membrane opening (BMO), anterior scleral canal opening (ASCO) areas, neural canal minimum cross-sectional area (NCMCA), and ASCO–BMO offset, were quantified via spectral-domain OCT. Visual field (VF) defects and parapapillary retinal nerve fiber layer (pRNFL) thickness were monitored over 3 years. Generalized linear mixed models and multivariate regression were used for analysis. Results: Compared with OAG, HMG eyes exhibited larger BMO areas (3.0 vs. 2.3 mm2, P < 0.001) and ASCO areas (2.6 vs. 2.4 mm2, P < 0.001), greater ASCO–BMO offset (376.1 vs. 161.5 µm, P < 0.001), smaller NCMCA (1.0 vs. 1.3 mm2, P < 0.001), and faster temporal VF progression (0.173 vs. 0.060 dB/y, P = 0.023) and pRNFL thinning (0.96 vs. 0.64 µm/y, P = 0.014). Multivariate analysis identified NCMCA as an independent predictor of global progression (β = −0.03, P = 0.021). Conclusions: HM-induced ONH deformation, particularly nasal tilting and reduced NCMCA, accelerates temporal glaucomatous damage. NCMCA serves as a critical biomarker for progression risk, supporting individualized management in glaucoma with HM.