Vision-specific quality of life and modes of refractive error correction

Purpose: Many studies currently use surveys to assess patients' reports of vision-specific quality of life to determine the impact of the disease or t he most appropriate mode of treatment. One such instrument, the National Ey e Institute Visual Function Questionnaire (NEI-VFQ), was developed to asses s vision-related quality of life with respect to emotional well-being and s ocial function as well as difficulty with tasks and symptoms. We administer ed the NEI-VFQ to 218 subjects free of eye disease to see if the survey was sensitive enough to detect differences in three modes of refractive error correction: spectacles, soft contact lenses, and rigid contact lenses. Meth ods: Surveys were administered, to 117 rigid contact lens wearers, 51 spect acle wearers, and 50 soft contact lens wearers. Kruskal-Wallis one-way anal ysis of variance was conducted to determine significant differences in each of the subscales. Results: The Peripheral Vision subscale score (mean a SD ) was 92.6 +/- 15.2 for the spectacle wearers, 100.0 +/- 0.0 for the soft c ontact lens wearers, and 98.3 +/- 7.1 for the rigid gas-permeable contact l ens wearers; the spectacle wearers' Peripheral Vision score was significant ly lower than the other two groups (Wilcoxon rank sum, p < 0.003 for both). The spectacle weavers (96.6 +/- 9.2) also had a significantly lower Depend ency subscale score than the rigid contact lens group (99.7 +/- 1.5) (Wilco xon rank sum, p = 0.001). There were no significant differences between the three groups detected in the mean of any of the other subscale scores. At least 50% of the subjects reported the maximum score for 6 of the 11 subsca les. Given our sample size, we have 100% power to detect a difference of 10 points with a SD of 10 at the <alpha> = 0.05 level. Conclusion: The NEI-VF Q is not appropriate for detecting significant differences in vision-relate d quality of life among spectacle, soft contact lens, and rigid gas-permeab le contact lens wearers, primarily due to maximum ratings by many of the su bjects. (Optom Vis Sci 2000;77:648-652).