Impact of smoking on choroidal microvasculature dropout in glaucoma: a cross-sectional study.

OBJECTIVE: To investigate the effect of smoking on choroidal microvasculature dropout (MvD) in glaucoma. DESIGN: Cross-sectional study. SETTING: Tertiary glaucoma centre. PARTICIPANTS: 223 eyes of 163 patients with primary open-angle glaucoma who had undergone imaging with optical coherence tomography angiography and completed a questionnaire on smoking from the Diagnostic Innovations in Glaucoma Study. PRIMARY OUTCOME MEASURES: Linear mixed-effects models were used to determine the effect of each parameter on MvD area and angular circumference. The sensitivity analysis was performed by categorising the glaucoma severity determined by visual field mean deviation (MD). RESULTS: MvD was found in 37 (51.4%) eyes with smoking history and in 67 (44.4%) eyes with non-smokers (p=0.389). Larger MvD area and wider angular circumference were found in smokers compared with non-smokers (p=0.068 and p=0.046, respectively). In a multivariable model, smoking intensity was significantly associated with MvD area (0.30(95% CI 0.01 to 0.60) each 0.01 mm2 per 10 pack-years; p=0.044). In eyes with moderate-severe glaucoma (MD <-6), smoking intensity was associated with larger MvD area (0.47 (95% CI 0.11 to 0.83) each 0.01 mm2 per 10 pack-years; p=0.011), whereas no significant association was found in early glaucoma (MD ≥-6) (-0.08 (95% CI -0.26 to 0.11), p=0.401). CONCLUSIONS: Smoking intensity was associated with larger choroidal MvD area in eyes with glaucoma, especially in patients with more severe disease. TRIAL REGISTRATION NUMBER: NCT00221897.