National study of cataract surgery outcomes. Variation in 4-month postoperative outcomes as reflected in multiple outcome measures

Abstract

Background: Although ophthalmologists have long recognized that visual acuity alone is an inadequate measure of visual impairment, the need for and outcomes of cataract surgery historically have been assessed in terms of visual acuity.

Purpose: To examine the relation among different cataract surgery outcome measures, including a 14-item instrument designed to measure functional impairment caused by cataract (the VF-14), at 4 months after cataract surgery.

Methods: The authors performed a longitudinal study of 552 patients undergoing first eye cataract surgery by 1 of 75 ophthalmologists practicing in Columbus, Ohio, St. Louis, Missouri, or Houston, Texas. Patients were interviewed, and clinical data were obtained preoperatively (July 15, 1991-March 14, 1992) and 4 months postoperatively.

Results: The percentage of patients judged to be improved at 4 months after cataract surgery varied by the outcome measure used: Snellen visual acuity (96%); VF-14 score (89%); satisfaction with vision (85%); self-reported trouble with vision (80%); and Sickness Impact Profile score (67%). The change in patients' ratings of their trouble with vision and their satisfaction with vision were correlated more strongly with the change in VF-14 score than with the change in visual acuity (operated eye or better eye). The average change in VF-14 score was unrelated to the preoperative visual acuity in the eye undergoing surgery.

Conclusion: Estimates of the proportion of patients benefiting from cataract surgery vary with the outcome measure used to measure benefit. Change in VF-14 score, a measure of functional impairment related to vision, may be a better measure of the benefit of cataract surgery than change in visual acuity.