Abstract
Purpose: :
To examine the association between longitudinal changes in visual acuity (VA) and Health Related Quality of Life (HRQOL) in Latinos participating in The Los Angeles Latino Eye Study (LALES).
Methods: :
Data for these analyses were collected for LALES, a population-based cohort study of eye disease in Latinos. Distance visual acuity (VA) was measured during a detailed ophthalmologic examination using standard ETDRS protocol at baseline (LALES I) and a follow-up examination (LALES II), approximately 4 years later. HRQOL was assessed at the LALES I and II examinations by the National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), composed of 12 vision-related scales. Scores were calculated using standard algorithms with a possible range of 0 to 100 and higher scores representing better functioning. Mean differences in HRQOL scores between baseline and follow-up were calculated for 3,169 participants with complete clinical examination and NEI-VFQ data at both time points; paired t-tests were used to estimate the significance of change (2-sided test). Mean differences and effect sizes (ES) for NEI-VFQ scores were calculated for 3 categories of VA change for the same time period (VA improved ≥ 2 lines, no change in VA, VA loss ≥ 2 lines).
Results: :
We observed statistically significant changes in mean NEI-VFQ-25 scores during the 4 year interval; significant changes (p<0.05) were found for 9 of 12 NEI-VFQ-25 scales and the composite score. For participants with a 2 line loss in VA over the 4 year period, we saw an approximate 5 point loss in the NEI-VFQ-25 composite score; the largest effect sizes were found for the driving difficulties (-0.42), mental health (-0.43), and dependency scales (-0.41). For participants with a 2 line improvement in VA over the 4 year period we also saw an approximate 5 point gain in the NEI-VFQ-25 composite score. The largest effect size (0.80) was observed for the driving difficulties scale. No measurable differences in HRQOL were observed for individuals without change in VA from LALES I to II.
Conclusions: :
Clinically important changes in VA were associated with significant changes in HRQOL using longitudinal data from a population-based sample of adults. A 2 line improvement in VA was associated with an approximate 5 point gain in the NEI-VFQ-25 composite score and a 2 line loss in VA was associated with an approximate 5 point loss. These results are consistent with previous findings based on cross-sectional data.
Keywords: visual acuity • quality of life