title: Visual discomfort and objective measures of static accommodation.
abstract: OBJECTIVE
  Accommodation insufficiency and fatigue have been associated with near work visual discomfort symptoms, but clinical measures of accommodation amplitude suggest insufficiency is uncommon and often not weak enough to cause symptoms. However, recent studies show that the clinical push-up test used to measure amplitude overestimates accommodative function. This study uses an open-field autorefractor to measure accommodative stimulus-response functions objectively in college students with and without near work induced discomfort symptoms.
  
  
  METHODS
  Using a Grand-Seiko WAM 5500 autorefractor, 2 min recordings were made each at five viewing distances (0 to 5 D) to measure an accommodative response function. Visual discomfort symptoms were assessed using the Conlon survey.
  
  
  RESULTS
  A strong and positive correlation between accommodative lag and visual discomfort symptoms was found under near work conditions. The prevalence of accommodative insufficiency was much higher than estimated by clinical measures.
  
  
  CONCLUSIONS
  Accommodative insufficiency and fatigue should be defined and described by objective methods using extended viewing times to assess function.
authors.affiliation: Colleges of Optometry and Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766-1854, USA. cchase@westernu.edu
authors.forename: Chris
authors.initials: C
authors.lastname: Chase
authors.forename: Chinatsu
authors.initials: C
authors.lastname: Tosha
authors.forename: Eric
authors.initials: E
authors.lastname: Borsting
authors.forename: William H
authors.initials: WH
authors.lastname: Ridder
mesh_terms: D000065:Accommodation, Ocular; D000293:Adolescent; D001248:Asthenopia / Q000175:diagnosis* / Q000503:physiopathology*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation; D005260:Female; D006801:Humans; D008297:Male; D009907:Optometry / Q000379:methods; D010775:Photic Stimulation / Q000379:methods; D011680:Pupil; D012029:Refraction, Ocular; D011795:Surveys and Questionnaires; D055815:Young Adult