Abstract:
The Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study found that that people with keratoconus and visual acuity 20/40 or better at baseline report a vision–related quality of life on the National Eye Institute Visual Function Questionnaire (NEI–VFQ) comparable to those with more clinically severe eye disease in several domains. We report longitudinal changes in VFQ scores in patients with keratoconus.
The NEI–VFQ was administered annually to keratoconus patients for seven years. Using regression, the slope of the scale score over time was calculated for patients with at least three reported visits. Where a patient underwent penetrating keratoplasty, observations were right–censored at the visit prior to surgery. Slopes were also calculated for changes in visual acuity and corneal curvature (steep keratometry). Association between changes in VFQ scale scores and clinical and demographic variables were assessed with regression using the scale's slope over time as the outcome.
In univariate analysis, patients reporting lower VFQ scores at baseline reported on average an improvement in quality of life over time, while those reporting higher scores at baseline reported a decrease. In multivariate analysis, including the baseline scale score as a covariate, an increase in corneal curvature was found to be significantly associated with a decline in the scores for Dependency, Mental Health, and Ocular Pain and Role Difficulties. A decrease in visual acuity was associated with a significant decrease in scores on the Dependency, Driving, Mental Health, and Near Activities scales.
There is preliminary evidence that people with keratoconus who have impaired vision–related quality of life accommodate their disease. However, it is clear that progression of disease as measured by changes in visual acuity and corneal curvature results in continued decline in vision–related quality of life.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • quality of life • keratoconus