The Potential Role of the Retinal Acuity Meter For Predicting Visual Outcome after Cataract Surgery

ABSTRACT

PURPOSE: To investigate the accuracy and usefulness of the retinal acuity meter (RAM) in predicting visual acuity after cataract surgery. METHODS: We randomly selected 47 eyes from 43 patients who underwent cataract surgery in our clinic. Preoperative BCVA and 3 month postoperative BCVA were measured by the Snellen chart, and we recorded the preoperative visual acuity by RAM. We also grouped the patients according to diabetic retinopathy and preoperative BCVA 20/100. By comparing the expected visual acuity by RAM with actual postoperative BCVA values, we analyzed the accuracy of the RAM's predictability after surgery. The cataract types and macular disease were taken under consideration when analyzing our results. RESULTS: Of the 47 eyes in our study, the postoperative Snellen visual acuity was predictable within three lines (90.9%) in 11 eyes with diabetic retinopathy and without macular disease. In the 36 eyes without diabetic retinopathy, the postoperative Snellen visual acuity was predictable within three lines (91.6%) of the cases. In both groups, the preoperative RAM acuity and postoperative BCVA were significantly correlated (R2=0.692, R2=0.812, p<0.05). In 41 eyes with preoperative BCVA 20/100 or more, the postoperative Snellen visual acuity was highly predictable in 95.1% (R2=0.763, p<0.05). However, in 6 eyes with preoperative BCVA levels less than 20/100, the postoperative Snellen visual acuity was not predictable (66.6 %). In the patients with both nucleosclerosis and posterior subcapsular opacity and in the patients with additional cortical opacity, the postoperative BCVA differed from the preoperative RAM acuity by more than three lines on the Snellen chart. CONCLUSIONS: RAM is useful in predicting postoperative visual acuity in cataract patients, but may be unreliable in the patients with combined cataract forms or with preoperative BCVAs less than 20/100.