title: The prevalence and types of strabismus, and average of stereopsis in Japanese adults.
abstract: OBJECTIVE
  Few studies report the prevalence and types of strabismus, or average of stereopsis in Japanese adults. We performed ophthalmological evaluation including motility and stereopsis during medical examinations at cooperative companies.
  
  
  METHODS
  We studies 1214 volunteers. The average age was 41.2 ± 12.6 (range 20-86) years. Examinations were carried out using their customary eyewear, evaluating alternate prism cover test (APCT), and Titmus stereo test (TST).
  
  
  RESULTS
  The mean horizontal angle at near distance (1/3 m) was 8.1 ± 6.0 Prism Diopter (PD), and vertical angle was 0.09 ± 1.0 PD. The total number of cases who had intermittent or constant tropia was 44 (3.6%), and the ratio of exotopia to esotropia (XT:ET ratio) was 18.5:1. The mean horizontal angle at far distance (5 m) was 3.9 ± 3.7 PD, and vertical angle was 0.09 ± 1.7 PD. The total number of cases who had intermittent or constant tropia was 21 (1.7%), and the XT:ET ratio was 7:1. The average TST was 50.1 ± 1.6 arcsec. 7.3% (n = 89) of the cases did not reach 100 arcsec.
  
  
  CONCLUSIONS
  We report detailed strabismus and stereopsis in Japanese adults. The XT:ET ratio was 18.5:1 in near distance, 7:1 in far distance. In our study, more than 60% of the cases of exotropia were convergence insufficiency type, and this may be a characteristic in Japanese adults.
authors.affiliation: Department of Ophthalmology, Kitasato University School of Medicine, 1-15-1, Kitasato, Sagamihara, Kanagawa, 252-0374, Japan. gosekikun@aol.com.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Goseki
authors.affiliation: Department of Ophthalmology, Kitasato University School of Medicine, 1-15-1, Kitasato, Sagamihara, Kanagawa, 252-0374, Japan.|Department of Orthoptics and Visual Science, School of Allied Health Sciences, 1-15-1, Kitasato, Sagamihara, Kanagawa, 252-0373, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishikawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003867:Depth Perception / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013285:Strabismus / Q000453:epidemiology* / Q000503:physiopathology; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity; D055815:Young Adult
keywords: Average stereopsis; Japanese adults; Prevalence of strabismus; Types of strabismus; XT:ET ratio