[Causes and prevalence of visual impairment in Japan].

To investigate the causes of visual impairment in Japan. The documents of 4,852 individuals with authorization of visual impairment registered between April 2007 and March 2010 in 7 randomly selected regions were reviewed. The major causes of visual impairment were glaucoma (21.0%), diabetic retinopathy (15.6%), retinitis pigmentosa (12.0%), macular degeneration (9.5%) and chorioretinal atrophy (8.4%). Individuals over 70 years of age were predominant for glaucoma, those aged 50-69 years for diabetic retinopathy and those under 40 years of age for retinitis pigmentosa. Sixty-one percent of persons affected by glaucoma were severely handicapped. Macular degeneration increased with age especially in individuals over 80 years of age. There was no difference in the order of major causes as compared with a previous report in 2001-2004. It is important to establish a central database system so that the data can be surveyed to provide more relevant information to understand current issues for handicapped persons and develop new prophylactic and therapeutic modalities.