Factors associated with macular vessel density measured by optical coherence tomography angiography in healthy and glaucomatous eyes

Purpose: To investigate factors associated with macular vessel density and to analyze their effects according to glaucoma stage. Study design: Retrospective cross-sectional study. Methods: A total of 72 healthy eyes and 147 open-angle glaucomatous eyes were studied. All eyes underwent optical coherence tomography and visual field examinations. Clinical variables were compared according to the glaucoma stage. Relationships between macular vessel density (mVD) and other variables were analyzed using linear regression and segmented analyses. Results: Age (P = 0.010) and signal strength (P < 0.001) were associated with macular vessel density in healthy eyes. In glaucomatous eyes, age, signal strength, ganglion cell-inner plexiform layer (GCIPL) thickness, and mean deviation (MD) correlated with macular vessel density (all P ≤ 0.005). When analyzed by glaucoma stage, age correlated with macular vessel density in early (P = 0.017 and all P ≤ 0.012, respectively) and moderate (P = 0.002 and all P ≤ 0.001, respectively) glaucoma. Conversely, GCIPL thickness was associated with macular vessel density (P = 0.004). According to segmented analysis between MD and mVD, the MD value at the change point for mVD was −17.92 dB, which was much lower than that for GCIPL thickness (−5.83 dB). Conclusion: Signal strength was the most significant factor associated with macular vessel density in healthy and glaucomatous eyes. Other than signal strength, factors associated with macular vessel density of glaucomatous eyes vary according to the glaucoma stage. The segmented analysis suggests that mVD could be better than GCIPL thickness in predicting MD changes in moderate-to-advanced glaucoma.