Study: Even small amount of iodine on silicone IOLs causes opacification

STOCKHOLM, Sweden — According to a surgeon speaking here, even a small amount of povidone iodine coming into contact with a silicone IOL during cataract surgery may cause opacification.

At the European Society of Cataract and Refractive Surgeons meeting, Siddhartha Goel, MD, recommended "extreme caution" in the prophylactic use of povidone iodine for infection at the end of cataract surgery and said that surgeons need to be careful to ensure complete wound closure.

In the study Dr. Goel presented, he and his colleagues exposed silicone IOLs to a number of chemicals used at each stage of cataract surgery. One IOL not exposed to chemicals was used as a control. All of the IOLs were then photographed against the same background in a medical photography studio.

The researchers found that all of the samples photographed were as clear as the control, except for those exposed to povidone iodine. Dr. Goel said that exposure to as little as 5% povidone iodine caused IOL opacification.

The hypothesis for this study arose from four cases of early postoperative opacification of silicone IOLs reviewed by the researchers, Dr. Goel said.

In those cases in which early postoperative opacification occurs, there could be an unobservable backflow process into the anterior chamber because such a low amount was able to cause opacification in the study, he said.

"We would recommend those who use povidone iodine to take every precaution they could possibly take to avoid allowing it into the anterior chamber at the end of surgery," he said.

Dr. Goel said while the toxifying effects of povidone iodine on the corneal endothelium are well known, the researchers were not aware of any studies of the effects of povidone iodine on IOLs. He recommended that more studies be performed on all IOL types.

All of the silicone IOLs tested were from the SI40 series and Clariflex model provided by Advanced Medical Optics, and all were made from the same silicone material.