Change of subjective visual function in first-eye cataract patients when the rate of surgery increases in a population

Abstract

Background: The increasing demand for cataract surgery has stimulated interest in outcome research and the potential public health impact of the intervention.

Objective: To determine the impact of an increased rate of first-eye cataract surgery on visual acuity (VA) and subjective visual ability/disability, before and after surgery, in a geographically defined population.

Research design: A prospective, observational study.

Subjects: All patients who had first-eye cataract extraction at one clinic during two separate 1-year periods. Five hundred seventy-six patients had surgery in 1997, and 353 had surgery in 1992 (17.2 and 10.6 per 1000 population 65 and older, respectively).

Measures: Best-corrected VAs were measured, and the patients answered self-administered questionnaires, before and after surgery. The questionnaires focused on the patients' subjective difficulties performing some common vision-dependent activities, such as reading, television-viewing, orientation, etc.

Results: In 1997 compared with 1992 the VA of the eye to be operated was on average better (chi2 for trend; P<0.0001), and the subjective visual disability was less before surgery (mean disability index 6.9 vs. 7.5; P<0.0001). There was also a smaller percentage of mature cataracts (15% vs. 23%; P<0.0001). After surgery the VA of the operated eye was better in 1997 (chi2 for trend; P<0.001), but there was no difference in improvement of subjective visual ability, nor change in subjective visual disability, compared with 1992. The patients' expectations and actual postoperative improvement of their ability to cope with daily life were higher in 1997 (chi2 for trend; P<0.0001 and P<0.001).

Conclusions: A higher frequency of first-eye cataract surgery in a population was before surgery associated with an on average better VA of the eye to be operated, a less perceived visual disability regarding some common vision-dependent activities, a lower percentage of mature cataracts and thus earlier surgery. Consequently, a higher rate of surgery would likely be associated with a lesser amount of visual impairment because of cataract in the population.