A comparison of methods for predicting visual acuity after cataract surgery

Abstract

Abstract: : Purpose:To compare the ability of various tests used for predicting visual acuity after cataract surgery. Methods:130 patients have been examined pre–operatively to date (mean age, 76.4 ± 8.9 yrs). Measurements included Critical Flicker/Fusion Frequency (CFF), Optimal Reading Speed, Displacement Threshold Hyperacuity (DTH), Super–illuminated Pinhole, PAM and Interferometry. Follow–up visits were conducted at least 8 weeks post–operatively. At present, post–operative data is available from 48 patients, 32 of these were cataract only patients, 9 of the subjects had cataract and ARMD, 6 subjects had cataract and POAG and 1 amblyope subject had cataract with ARMD. All subjects underwent successful phacoemulsification and IOL implantation. Results:Mean pre–operative visual acuity was 0.45 ± 0.40 (Snellen equivalent 20/57) with a post–operative mean value of 0.14 ± 0.21 (Snellen equivalent 20/28). Scatterplots comparing pre– (y axis) and post–operative (x axis) data for 48 subjects produced the following results: CFF (r² = 0.77, y = 0.88x + 4.76); Optimal Reading Speed (r² = 0.45, y = 0.98x – 14.07); Super–illuminated Pinhole (r² = 0.35, y = 0.67x + 0.22); DTH (r² = 0.06, y = 0.42x + 76.50); Interferometry (r² = 0.04, y = 0.35x + 0.21) and PAM (r² = 0.03, y = 0.26 x + 0.22). Conclusions:The coefficients of determination indicate the degree of association between pre– and post–operative performance. This is poor for PAM and Interferometry. The association and therefore the predictability of the other tests are better with CFF being particularly good.

Keywords: cataract • age–related macular degeneration • visual acuity