Effect of intraocular lens asphericity on posterior capsule opacification between two intraocular lenses with same acrylic material: a fellow-eye study

Purpose: To evaluate intra-individual differences in posterior capsule opacification (PCO) and visual performance between spherical AcrySof SN60AT and an aspheric AcrySof SN60WF intraocular lens (IOL) with a posterior aspheric surface, both of which are made of same hydrophobic acrylic material. Setting: Ophthalmology Department, St Thomas' Hospital, London, UK. Methods: In this prospective randomized, fellow-eye comparison, an aspheric IOL, which is 9% thinner in comparison with the spherical IOL, was randomized to the first eye of 47 patients and fellow-eye surgery was performed within 3 weeks. Follow-up was at 1, 3, 6, 12 and 24 months. Corrected logMAR visual acuity (CDVA) was measured at 100% and 9% contrast. After pupil dilation, digital retroillumination photographs were taken and the mean PCO percentage was calculated using poco software at each follow-up visit. Results: At 1, 3, 6, 12 and 24 months, 47 (94 eyes), 44 (88 eyes), 42 (84 eyes) and 41 (82 eyes) patients were followed-up respectively. Hundred per cent and 9% of LogMAR CDVA was not significantly different between the two IOLs (p = NS at all time-points). Percentage area PCO scores (mean +/- SD) at 1, 3, 6, 12 and 24 months with the spherical IOL was 5.82 +/- 9.89, 7.76 +/- 16.83, 7.21 +/- 12.46, 9.29 +/- 18.25 and 14.39 +/- 25.42, respectively, and with an aspheric IOL was 8.91 +/- 12.79, 5.97 +/- 10.32, 5.15 +/- 7.92, 7.68 +/- 11.18 and 12.18 +/- 20.10, respectively (p = NS at all time-points). Conclusions: Posterior capsule opacification was not significantly different between the spheric and aspheric IOLs in this fellow-eye, randomized comparison. Additional asphericity on the existing model of IOL does not influence PCO performance.