Harold Ridley implanted his first intraocular lens (IOL) as a secondary procedure some 3 months after the primary extracapsular extraction. By serendipity, this changed the course of ophthalmic surgery because by this time the posterior capsule had become fibrosed to support the weight of the lens implant, achieving an anatomically successful operation: had the implant been done as a primary procedure (as was later the case) failure would have been inevitable and the course of history may well have changed.1 The history of implant surgery and the management of posterior capsule opacification (PCO) since then has gone hand in hand.

PCO is caused by residual lens epithelial cells (LECS) which are inevitably left in the bag and then undergo proliferation and metaplasia. Clinically the anterior LECS surrounding the rhexis seem more likely to express α smooth muscle actin and become myofibroblasts while the equatorial cells are more likely to form Elschnig's pearls although a cell biological understanding of why this should be so is lacking. Vision is lost from either forward light scattering into the eye by the PCO or from movement and decentration of the IOL.

PCO was regarded as an inevitable consequence of lens implant surgery until the introduction of the Acrysof IOL by Alcon Laboratories in 1993. In the early clinical trials a German surgeon, Dr Eckhard Medhorn, made the astute observation that his patients had unusually clear posterior capsules; the reason for this was unknown and Alcon looked for research to substantiate this. The study of PCO at the time was greatly hampered by the lack of …