The risk of blindness from glaucoma can be reduced by early detection and treatment. A domestic large-scale surveillance (Tajimi Study) shows that approximately 90% of glaucoma patients of 40 years or older are undiagnosed, and initiation of the treatment is delayed. In this study the glaucoma treatment was investigated to understand the real-world situation of glaucoma therapy using claim data in Japan. METHODS: This was a retrospective cohort study. The data were extracted from a Japanese healthcare database (MinaCare Co., Ltd), which contained claim data obtained from approximately 2.0 million members of employment-based health insurance groups and their dependents. The ICD-10 classification was used to identify glaucoma patients. A washout period of 6 months before enrollment was set during which there were no records of prescriptions of antiglaucoma drugs or glaucoma surgery. Antiglaucoma ophthalmic solutions or surgery for initial treatment, persistence and change in medication were investigated. RESULTS: Out of 2,074,499 people in the database as of August 2014, we identified 42,470 glaucoma patients and the target group who met the wash-out conditions involved 6,333 patients (male: 3,618; female: 2,715). About 75% of the patients were between 40 to 69 years old and about 10% were 70 years or older. Regarding the initial treatment, most patients started with topical antiglaucoma treatment and only 24 patients underwent surgery. The first prescription of antiglaucoma drug included 1 agent in 87%, and cases with 2 agents (10%), 3 agents (3%), or more than 3 agents (0.3%) were also identified. The most prescribed one was latanoprost (26%) followed by tafluprost (17%), and carteolol (10%). CONCLUSIONS: In this study, the initial treatment in most of the patients followed the treatment guidelines. However, lack of disease awareness among potential patients and accessibility to early screening and diagnosis of glaucoma may exist, and it should be given sufficient consideration.