This study aimed to survey the effect of androgen deprivation therapy (ADT) on the development of open angle glaucoma (OAG) in prostate cancer using the data from national health insurance research database (NHIRD) of Taiwan. A retrospective cohort study was conducted and patients were regarded as prostate cancer with ADT according to related diagnostic, procedure and medication codes. Each prostate subject with ADT was matched to one patient with prostate cancer, but without ADT, and two participants without both prostate cancer and ADT; 1791, 1791 and 3582 patients were recruited in each group. The primary outcome was set as the OAG development according to related diagnostic codes. Cox proportional hazard regression was used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) of ADT for the incidence of OAG. There were 145, 65 and 42 newly developed OAG cases in the control group, prostate cancer without ADT group and prostate cancer with ADT group. The prostate cancer with ADT group showed a significantly lower risk of OAG development compared to the control group (aHR: 0.689, 95% CI: 0.489–0.972, p = 0.0341), and the risk of OAG development in the prostate cancer without ADT group was similar compared to that in the control group (aHR: 0.825, 95% CI: 0.613–1.111, p = 0.2052). In addition, ages older than 50 years old would lead to higher incidence of OAG development, respectively. In conclusion, the use of ADT will lead to a similar or lower rate of OAG development.