Foldable vs rigid lenses after phacoemulsification for cataract surgery: a randomised controlled trial

To compare the outcomes of phacoemulsification with either a 2.5-mm clear corneal incision and a foldable intraocular lens (IOL) or a 5-mm sclerocorneal tunnel incision and a rigid polymethyl methacrylate (PMMA) IOL.

In a prospective, randomised clinical trial of phacoemulsification cataract surgery, 1200 patients received either a foldable hydrophilic acrylic IOL through a 2.5-mm corneal incision or an inexpensive rigid PMMA IOL via a 5-mm sclerocorneal tunnel. Intra- and post-operative data and visual acuity at discharge, 6 weeks, and 1 year follow-up were analysed.

At 1 year after surgery, 996 (83.0%) patients were followed up with an uncorrected visual acuity of 6/18 or better in 90.3% of the foldable and 94.3% in the rigid IOL group (risk ratio (RR) 0.96, 95% confidence intervals (CI) 0.92-0.99). Poor outcome (best-corrected acuity 6/60 or worse) occurred in 1.0% and 0.4%, respectively (RR 4.28, 95% CI 0.48-38.18). The surgical cost of consumables and overall surgical time were similar in both groups; however, the cost of the foldable IOL was eight times higher than the PMMA IOL. Posterior capsule opacification was more common in the rigid IOL group at 12 months (36.1% vs 23.3%); however, this did not affect post-operative vision.

In the hands of experienced cataract surgeons, phacoemulsification with implantation of a foldable or a rigid IOL gives excellent results. Using an inexpensive rigid PMMA IOL will make phacoemulsification more affordable for poor patients in low- and middle-income countries.