Potential acuity meter to predict postoperative visual acuity.

Thirty-three eyes were examined with the potential acuity meter (PAM) to determine preoperatively the expected visual acuity for patients undergoing cataract surgery. The preoperative visual acuity was compared to the best postoperative visual acuity. Although several patients had moderate macular degeneration as well as cataracts, there was an overall accuracy to within two lines of the best visual acuity in 96% of patients. There was a tendency to underestimate rather than overestimate postoperative visual acuity when these readings were in error. The instrument was only used if the cataract examined had some clarity. Older patients who were unsteady had difficulty performing the test.