title: Accommodation and pupillary response in early-onset myopia among schoolchildren.
abstract: OBJECTIVE
  To investigate changes in accommodation and pupillary reaction in early-onset myopia among children.
  
  
  METHODS
  An objective infrared optometer and a pupillometer were used to evaluate simultaneously tonic accommodation, accommodative response, accommodative adaptation, and pupil diameter in 19 schoolchildren with early-onset myopia and 15 age-matched emmetropic controls.
  
  
  RESULTS
  Tonic accommodation in the early-onset myopes (1.03 D) was significantly less than in the emmetropes (1.37 D) (p < 0.05), whereas accommodative response and accommodative adaptation showed no significant difference between the early-onset myopes and emmetropes. The average pupil diameter after 20 min of dark adaptation in the early-onset myopes was 4.52 mm, which was significantly smaller than that in the emmetropes (5.21 mm) (p < 0.05). During nearwork stimulation, the average pupil diameter further decreased to 3.83 mm in the early-onset myopes and 4.78 mm in the emmetropes (p = 0.003).
  
  
  CONCLUSIONS
  These results suggest that low tonic accommodation and small pupil diameter may play important roles in the pathogenesis of early-onset myopia among schoolchildren.
authors.affiliation: Department of Ophthalmology, Taipei Municipal Yangming Hospital, Taiwan. wounglc@health.gov.tw
authors.forename: L C
authors.initials: LC
authors.lastname: Woung
authors.forename: Y F
authors.initials: YF
authors.lastname: Lue
authors.forename: Y F
authors.initials: YF
authors.lastname: Shih
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D002648:Child; D003623:Dark Adaptation; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology*; D011680:Pupil / Q000502:physiology*