Abstract:AIM: To investigate the relationship between choroidal thickness (CT) and primary open angle glaucoma (POAG) in highly myopic eyes across different categories of myopic atrophic maculopathy (MAM). METHODS: This observational analytical case–control study enrolled highly myopic patients. All participants underwent comprehensive ophthalmic examinations. CT was measured in peripapillary and macular regions using optical coherence tomography (OCT). Each eye was classified for POAG status and MAM category. Stepwise logistic regression was performed to identify factors independently associated with POAG. RESULTS: Among 248 highly myopic subjects, 37 (18 males, mean age 68.25±7.16y) had POAG (25 bilateral, 12 unilateral) and 211 (97 males, mean age 67.09±7.63y) were non-glaucomatous. Age and sex did not differ significantly between groups (both P>0.05). Seventy-eight patients had unilateral high myopia and 170 bilateral, yielding 418 highly myopic eyes, of which 58 (13.88%) had POAG. POAG prevalence across MAM categories (no lesion to complete macular atrophy) was 7.14%, 16.28%, 14.07%, 17.86%, and 17.14%, respectively (P=0.44). In the diffuse chorioretinal atrophy subgroup, POAG eyes showed significantly thicker CT in central, inner nasal, outer superior, inner superior, and inner inferior macular regions, and thinner central corneal thickness (all P<0.05). Stepwise logistic regression showed that only parafoveal inferior CT was independently associated with POAG in this subgroup (OR=1.017; 95%CI: 1.005–1.028; P<0.01). No significant CT–POAG association was found in other MAM categories. CONCLUSION: Increased macular CT is independently associated with POAG in highly myopic eyes with diffuse chorioretinal atrophy. This implies distinct pathogenic mechanisms underlying POAG development across different MAM categories in high myopia.