Implementation methods for vision related quality of life questionnaires

AIM To determine to the most reliable and consistent method, and time interval over which to implement a vision-impairment quality-of-life assessment tool.
METHOD 117 low vision patients aged 9-101 years were assigned into 3 age, gender and visual function matched groups (n=39 in each) to answer the Low Vision Quality-of-Life (LVQOL) by post, telephone or in-person. The LVQOL was completed on 4 occasions, each separated by 4 weeks.
RESULTS Postal implementation was the most cost effective method, showed the highest internal consistency of LVQOL items, but resulted in a lower apparent quality-of-life score than either phone or in-person interviews (p<0.001). There was no difference in test-retest reliability between the 3 methods of implementation (p=0.12). The profile of LVQOL scores showed a trend towards reduced quality-of-life scores three months after baseline measures.
CONCLUSION Posting may be the method of choice for clinical measurement of vision-related quality-of-life. Patients with greater visual impairment were no less likely to complete a questionnaire when implemented by post and there was no apparent bias from other people assisting them. The quality-of-life measure can occur at any time up to 2 months after low vision rehabilitation for the progressive nature of conditions causing low vision not to cause a decreased baseline score. The LVQOL was shown to be a highly internally consistent and reliable method for measuring quality-of-life in the visually impaired.