title: Clinical testing of accommodative facility: part III. Masked assessment of the relation between visual symptoms and binocular test results in school children and adults.
abstract: BACKGROUND
  Accommodative facility is commonly assessed using +/- 2.00 lenses at 40 cm. Significant differences have been demonstrated on binocular facility testing between symptomatic and asymptomatic children; studies on adults have not replicated these results. We evaluate the relation between symptoms and binocular amplitude-scaled facility (equivalent stimulus for each subject based on individual amplitude).
  
  
  METHODS
  Optometry students (N = 98) and school children IN= 152) participated in a vision screening. A 9-question standardized questionnaire quantified symptoms. Binocular accommodative facility was assessed using random presentation of standard and amplitude-scaled facility, without knowledge of symptom level. Subjects with abnormal binocular vision were excluded from data analysis.
  
  
  RESULTS
  For children, both amplitude-scaled (p = 0.0004). and standard accommodative facility (p = 0.0055) significantly differentiated symptomatic from asymptomatic responses. For adults, amplitude-scaled responses were significantly different (p= 0.0228) between symptomatic and asymptomatic subjects; standard testing results were not (p = 0.2013).
  
  
  CONCLUSIONS
  Binocular amplitude-scaled facility testing (test distance 45%, lens power range 30% of push-up amplitude) identifies symptomatic adults at high significance level. And both children and adults perform similarly on amplitude-scaled testing. These results suggest that amplitude-scaled binocular accommodative facility should be the test of choice for evaluation of patients between the age of 8 years and the onset of presbyopia. Patients who perform less than 10 cycles per minute are likely to be symptomatic.
mesh_terms: D000065:Accommodation, Ocular; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D016037:Single-Blind Method; D014786:Vision Disorders / Q000175:diagnosis / Q000503:physiopathology; D014787:Vision Tests; D015348:Vision, Binocular