Clinical testing of accommodative facility: part III. Masked assessment of the relation between visual symptoms and binocular test results in school children and adults.

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). CONCLUSION: 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.