Relationship among Water-Shed Zone, Nocturnal Dip and Visual Field Progression in Open Angle Glaucoma

Purpose: To investigate the influence of water-shed zone (WSZ) and nocturnal dip (ND) on the progression of the glaucomatous visual field (V/F) defects in open-angle glaucoma (OAG) patients when the intraocular pressure (IOP) was maintained under the target pressure.Methods: We performed fluorescence angiography (FAG), 24-hour ambulatory blood pressure monitoring (24-hr ABPM), and V/F tests.We examined the relationships among WSZ in early-FAG, ND over 10% (dip), and the progression of the glaucomatous V/F defects using chi-square, Fisher's exact, and multivariate logistic regression tests.A p-value < 0.05 was considered statistically significant.Results: When considering the correlation between WSZ and dip, statistical significance was found in OAG (p = 0.024, odds ratio (OR) = 3.308) and normal tension glaucoma (NTG) (p = 0.029, OR = 4.364) patients.In patients with dip, glaucomatous V/F defects significantly progressed (OAG: p = 0.003, OR = 5.938, NTG: p = 0.005, OR = 13.929).In patients with WSZ, the glaucomatous V/F defects progressed in all groups (OAG: p = 0.002, OR = 5.156, NTG: p = 0.024, OR = 4.750, primary open angle glaucoma (POAG): p = 0.021, OR = 8.750).In the patients with WSZ involving optic nerve head, the glaucomatous V/F defects had progressed in OAG (p = 0.004, OR = 5.958) and NTG (p = 0.009, OR = 8.333) groups.Based on binary logistic regression analysis, dip (p = 0.010, OR = 6.227) significantly affected V/F progression only in OAG patients.Conclusions: In the OAG and NTG groups, ND over 10% influenced the progression of the glaucomatous V/F defects.The patients with WSZ tended to have ND over 10% in OAG and NTG groups and glaucomatous V/F defects progressed in all patients.Therefore, performing early FAG and 24-hr ambulatory blood pressure monitoring may be helpful for glaucoma patients with progressing glaucomatous V/F defects even when the IOP was maintained under the target pressure.