Comparison of Quality-of-Life Instruments in Adults with Strabismus

Abstract

To compare two health-related quality-of-life (HRQOL) questionnaires in adults with strabismus: the new 20-item Adult Strabismus (AS-20) questionnaire (developed specifically for Adult Strabismus) and the 25-item National Eye Institute Visual Function Questionnaire (VFQ-25). Cross-sectional study. Eighty-four adult patients with strabismus (median age, 53 years; range, 18 to 81 years) completed the AS-20 and VFQ-25 HRQOL questionnaires. Patients were categorized as diplopic (n = 65) or nondiplopic (n = 19). Subnormal HRQOL was defined as less than the fifth percentile for adults with no visual impairment. The proportion of patients below normal was compared overall and by diplopia status. Overall, more patients scored below normal with the AS-20 than with the VFQ-25 (90% vs 29%; P < .0001). Nondiplopic patients more often were below normal on the AS-20 psychosocial subscale than on the function subscale (95% vs 42%; P = .002), whereas diplopic patients were more often below normal on the function subscale (85% vs 68%; P = .01). On the psychosocial subscale, more nondiplopic than diplopic patients scored below normal (95% vs 68%; P = .01); on the function subscale, more diplopic than nondiplopic patients scored below normal (85% vs 42%; P = .0005). The VFQ-25 seemed to be insensitive to nondiplopic strabismus: no patients scored below normal on composite score and no more than 11% scored below normal on VFQ-25 subscales. Of diplopic patients, 37% scored below normal on VFQ-25 composite score. No more than 38% scored below normal on VFQ-25 subscales. The new AS-20 seems to be more sensitive than the VFQ-25 for detecting reduced HRQOL in Adult Strabismus, and therefore may be a more useful tool for clinical assessment and clinical trials.