OBJECTIVE: To determine the most appropriate method for measuring the effect on contrast sensitivity of neodymium:YAG (Nd:YAG) posterior capsulotomy for early posterior capsular opacification (PCO).DESIGN: Prospective comparison of five different methods for luminous contrast sensitivity testing in patients undergoing capsulotomy.PARTICIPANTS: Sixteen patients with PCO involving the visual axis and visual acuities of 20/40 or better were recruited sequentially.INTERVENTION: All patients were tested with each of the five tests before and after Nd:YAG capsulotomy.MAIN OUTCOME MEASURES: The contrast sensitivity function was measured with variable contrast sine wave gratings using the Vistech VCTS 6500, Mentor B-VAT-II and a computer graphics system. Peak contrast sensitivity at 3 cyc/deg was compared with two letter tests, the Pelli-Robson chart, and a computer that generated optotypes.RESULTS: Significant generalized improvement that was not frequency selective was measured over the entire contrast sensitivity function after capsulotomy. The five tests did not significantly differ (P > 0.05) in their measurement of peak contrast sensitivity (3 cyc/deg) improvement after capsulotomy. Letter-based tests showed better agreement and lower variance than gratings tests. Visual acuity and contrast sensitivity improvement were poorly correlated.CONCLUSIONS: This study shows that contrast sensitivity is adequately documented by a single measurement at 3 cyc/deg, is an informative supplement to visual acuity, and that little extra information is to be gained by measuring further spatial frequencies in eyes with PCO. Peak contrast sensitivity is best determined using a letter-based test.
Aged Aged, 80 and over