Responsiveness of the National Eye Institute Refractive Error Quality of Life Instrument to Surgical Correction of Refractive Error
Published in: Ophthalmology, v. 110, no. 12, Dec. 2003, p. 2302-2309
Posted on RAND.org on December 31, 2002
OBJECTIVE: Refractive error and the means by which it is corrected may impact substantially on quality of vision and health-related quality of life in ways not captured adequately by standard measures of visual acuity. The goal of this analysis was to evaluate the responsiveness of the National Eye Institute Refractive Error Quality of Life (NEI-RQL) instrument to surgical correction of refractive error. DESIGN: Prospective, multicenter cohort study. PARTICIPANTS: The NEI-RQL, a 42-item measure with 13 scales, was self-administered by 185 patients before and after undergoing surgical correction of myopic or hyperopic refractive error. Preoperative and postoperative clinical information was collected, including refractive error and corrected visual acuity. METHODS: Differences between preoperative and postoperative NEI-RQL scores were examined. Responsiveness was assessed using the standardized response mean and the responsiveness statistic. The authors also compared scales using relative efficiency estimates. MAIN OUTCOME MEASURES: Changes in NEI-RQL scales (clarity of vision, expectations, near vision, far vision, diurnal fluctuations, activity limitations, glare, symptoms, dependence on correction, worry, suboptimal correction, appearance, and satisfaction with correction). RESULTS: For myopes and hyperopes combined, refractive surgical correction was associated with statistically significant (P<0.05) improvements in scores for 11 of 13 scales. The largest improvements, ranging from 26 to 58 points on the 0 to 100 possible score range, were seen in expectations, activity limitations, dependence on correction, appearance, and satisfaction with correction. Separate analysis of myopes and hyperopes revealed similar effects in the 2 groups. Baseline scores were found to be predictive of change after surgery. CONCLUSIONS: The NEI-RQL is responsive to changes in vision-targeted health-related quality of life resulting from keratorefractive surgery. This instrument may prove useful for evaluating the beneficial and adverse impacts of surgical and nonsurgical methods of refractive error correction.