The Japan Glaucoma Society has said that an estimated 4 million people in this country suffer glaucoma, an eye disease that causes a decrease or complete loss of vision, and urged improved checkups.

The society said that a study it conducted indicates that one in 17 Japanese over age 40 has glaucoma. The prevalence rate is 5.8 percent, almost double that of Caucasians.

The group is urging Health, Labor and Welfare Minister Chikara Sakaguchi to expand ophthalmic examinations for early detection of the disease.