Long-term efficacy of adding a sharp posterior optic edge to a three-piece silicone intraocular lens on capsule opacification: five-year results of a randomized study

Purpose To compare the intensity of capsule opacification with the sharp and the round optic edge variant of an open-loop hydrophobic silicone intraocular lens (IOL). Design Randomized, controlled, double-blind clinical trial with intraindividual comparison. Methods Fifty-one patients with bilateral age-related cataract were included (102 eyes). Each patient had had cataract surgery in both eyes and received a Microsil IOL with a sharp optic edge design (model S) in one eye and a Microsil IOL with a round optic edge design (model R) in the fellow eye. Both IOLs had an identical haptic design (nonangulated polymethylmethacrylate) and silicone optic material. The patients were examined at the slit lamp, best-corrected visual acuity was assessed, and standardized high-resolution digital retroillumination images of the posterior capsule were taken 5 years after surgery. The intensity of regeneratory posterior capsule opacification (rPCO), fibrotic PCO (fPCO), and anterior capsule opacification (ACO) was assessed subjectively at the slit lamp, and of rPCO, objectively using automated image analysis software (AQUA). The need for an Nd:YAG laser capsulotomy (Nd:YAG-LCT) was noted. Results The mean AQUA PCO score was 1.2 for the model S and 2.4 for the model R lens ( P = .001). The model S lens also led to less peripheral fPCO ( P = .003). Concerning ACO, there was no significant difference between both IOL groups ( P = .72). Whereas no capsulotomy was required with the model S, four cases (16%) had been performed in the model R group. Conclusion Five years postoperatively, the sharp-edged silicone IOL showed less rPCO and fPCO than the round-edged IOL. However, regarding ACO, there was no significant difference between both IOL styles.