Successful IOL implantation depends on PCO prevention

Results of a recent study examining adult autopsy globes show that implants fabricated from hydrophobic acrylic material (AcrySof, Alcon Laboratories) are associated with a much higher rate of posterior capsule opacification (PCO) than previously thought. It had been believed that this IOL was associated with low PCO rates and, therefore, it was being implanted in up to 96% of paediatric cataract surgery cases.

"We now know that the PCO rate is [about] 35%, no different from many other lenses," said Brian E. Zaugg, a medical student at the University of Utah, Salt Lake City, USA, and research fellow with the David J. Apple, MD, Laboratory for Ophthalmic Devices Research, Sullivan's Island, South Carolina, USA. "This puts into question the arbitrary use of only one IOL design in children.

"Our study shows that the postoperative time is actually the major factor associated with PCO development," Zaugg added. "Also considering that, when compared with adult eyes undergoing cataract surgery, paediatric eyes exhibit more rapid lens epithelial cell (LEC) proliferation and the IOL remains in the eye for a much longer duration, paediatric implants will have a much lesser chance to ward off PCO.

Study data

This study, which was conducted with Dr Apple, included 500 cadaver eyes that were post-extracapsular cataract extraction and lens implantation obtained between 2004 and 2007. The focus was on AcrySof IOLs, because according to a 2007 survey conducted by Wilson et al., they represent more than 96% of implants used in paediatric cataract surgery.

The data this far were obtained on the three-piece AcrySof IOLs because the single-piece lens model has only recently become available for accession in the laboratory's autopsy database, Zaugg noted. However the biomaterial used to fabricate the lens has remained unchanged.

"In summary, we have come a long way toward achieving our goal of safe and effective paediatric surgery," Zaugg concluded. "But in both adults and children we do need to attack the root of the problem by finding better means of removing lens material from the capsular bag, for example, using pharmacologic strategies."

Brian E. Zaugg is a medical student at the University of Utah, Salt Lake City, USA and a research fellow with the David J. Apple, MD, Laboratory for Ophthalmic Devices Research, Sullivan's Island, South Carolina, USA. He can by contacted by E-mail: brzaugg@hotmail.com

Mr Zaugg does not hold a proprietary interest in the subject matter.