title: Prevalence of visual impairment in the adult Japanese population by cause and severity and future projections.
abstract: OBJECTIVE
  To present a comprehensive estimate of the total number of people with visual impairment in the adult Japanese population by age, gender, severity and cause, and to estimate future prevalence based on population projections and expected demographic changes.
  
  
  METHODS
  Definitions of visual impairment used in this study were based on the United States criteria. Total visual impairment was calculated as the sum of low vision and blindness. The prevalence estimates were based on input from a number of Japanese epidemiological surveys, census material and official population projections.
  
  
  RESULTS
  There were an estimated 1.64 million people with visual impairment in 2007 in Japan. Of these, 187,800 were estimated to be blind. The prevalence of visual impairment in Japan increased with age and half of the people with visual impairment were aged 70 years or older. The leading causes of visual impairment in Japan were glaucoma (24.3%), diabetic retinopathy (20.6%), degenerative myopia (12.2%), age-related macular degeneration (10.9%), and cataract (7.2%). These five major causes comprised three-quarters of all visual impairment. The prevalence of visual impairment was projected to increase from 1.3% of the population in 2007 to 2.0% by 2050.
  
  
  CONCLUSIONS
  This comprehensive study presents the prevalence of total visual impairment in the adult Japanese population. The projected increases in the prevalence of visual impairment over time reflect the demographic changes of a declining and aging Japanese population. These projections highlight that the burden of disease due to visual impairment and imposed on society is likely to increase.
authors.affiliation: National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan. yamadamasakazu@kankakuki.go.jp
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yamada
authors.forename: Yoshimune
authors.initials: Y
authors.lastname: Hiratsuka
authors.forename: Chris B
authors.initials: CB
authors.lastname: Roberts
authors.forename: M Lynne
authors.initials: ML
authors.lastname: Pezzullo
authors.forename: Katie
authors.initials: K
authors.lastname: Yates
authors.forename: Shigeru
authors.initials: S
authors.lastname: Takano
authors.forename: Kensaku
authors.initials: K
authors.lastname: Miyake
authors.forename: Hugh R
authors.initials: HR
authors.lastname: Taylor
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000208:ethnology; D001766:Blindness / Q000453:epidemiology* / Q000209:etiology; D005128:Eye Diseases / Q000150:complications*; D005260:Female; D005544:Forecasting; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012720:Severity of Illness Index; D017678:Sex Distribution; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*