Abstract
Abstract: :
Purpose: Potential acuity testing prior to cataract surgery can help provide a more realistic expectation of post-operative acuity. We compare the accuracy of the Potential Acuity Meter (PAM) and the Illuminated Near Card (INC) in this prospective study. Methods: During pre-surgical evaluations from November, 2000 to September, 2002, both PAM and INC tests were given to each study patient following dilation with 1% tropicamide. Patients then rated the subjective ease of use of each test. Best spectacle corrected visual acuity (BSCVA) was recorded at 1, 4, and 12 weeks post-operatively. McNemar’s Χ2 test for paired associations was used to analyze categorical data; paired t-tests were used for continuous variables. Results: In our study group of 124 eyes of 124 patients, the INC was more likely to predict BSCVA within 1 Snellen line (p=0.002) than the PAM, but this difference decreased for accuracy within 2 lines (p=0.16). The PAM predicted BSCVA within 1 line in 87 (70.2%) eyes, compared to 102 (82.3%) by the INC. The PAM was accurate within 2 lines for 109 (87.9%); the INC was accurate in 115 (92.7%) eyes. The PAM was more likely to underpredict potential acuity (p<0.001), while the INC was more likely to overpredict (p=0.004) or give exact predictions of BSCVA (p<0.001). Accuracy of the INC declined in eyes with macular comorbidity, so that no significant differences in accuracy remained between the two tests. In these 41 eyes, the INC and PAM predicted acuity within 1 line in 30 (73.2%) and 29 (70.7%) eyes, respectively. Both tests accurately predicted potential acuity within 2 lines for 37 (90.2%) eyes. Of the 120 patients for which information was available, the PAM and the INC were rated as "easy" tests by 54 (45.0%) and 94 (78.3%) patients, respectively. Conclusions: Both the PAM and the INC are useful for predicting BSCVA after phacoemulsification, but the PAM is more likely to underestimate potential acuity. The INC has better accuracy in patients without macular comorbidity and is easier for patients to use, but may overestimate potential acuity.
Keywords: cataract • treatment outcomes of cataract surgery • macula/fovea