Glaucoma is a disease where the field of vision is gradually reduced due to damage on the optical nerve caused by eye pressure. In Japan, it is the number one cause of blindness that is not from birth. About one person aged forty and over out of twenty is affected by glaucoma, and the ratio increases with age.
As it can be difficult for patients to detect the condition by themselves until the latter stages, approximately 90% of people are said to have undetected glaucoma. There are several types of glaucoma, but even people with normal eye pressure can develop normal-tension glaucoma, a type that the majority of Japanese glaucoma patients have.
It is very important to receive examinations and treatment by an ophthalmologist, including regular visual field tests to monitor the progression of the condition. Recently by examining the thickness of the optic disc (or optic nerve head) and the retina through optical coherence tomography (OCT), accurate diagnosis and monitoring have been made possible.