Predicting Lifetime Transition Risk of Severe Visual Field Defects Using Monte Carlo Simulation in Japanese Patients with Primary Open-Angle Glaucoma

Purpose To maintain visual fields and quality of life over a lifetime, medical practice must be conducted taking into consideration not only visual field progression but also future visual field changes that occur over the patients' expected lifespan. The purpose of this study is to investigate the feasibility of establishing a model that predicts prognosis, estimating the proportion of glaucoma patients with severe visual field defects. Patients and Methods The data of 191 patients with primary open-angle glaucoma, with a predominance of normal-tension glaucoma, were used for this study. The model was developed based on patients' backgrounds and risk factors, using Monte Carlo simulation. A "severe visual field defect" was defined as ≤-20 dB. The mean deviation (MD) value for 10,000 virtual patients in each simulation pattern (144 patterns) was calculated using a predictive formula to estimate the MD slope, and the effects of risk factors and intraocular pressure (IOP) reduction on the proportion of patients with severe visual field defects were evaluated. Results Younger age, later-stage disease, more severe glaucomatous structural abnormalities and the presence of disc hemorrhage were associated with an increase in the progression rate of patients with severe visual field defects. Conversely, lower IOP was associated with a decrease in this rate. Conclusion Combining regression analysis with Monte Carlo simulation could be a useful method for developing predictive models of prognosis in glaucoma patients.