Multiple factors guide IOL choice

March 15, 2007

Las Vegas-When capsule fixation is not an option, the cataract surgeon should select an IOL and fixation technique based on personal experience, skill, and comfort level while also considering the specific clinical presentation of the patient, said Roger F. Steinert, MD.

Las Vegas-When capsule fixation is not an option, the cataract surgeon should select an IOL and fixation technique based on personal experience, skill, and comfort level while also considering the specific clinical presentation of the patient, said Roger F. Steinert, MD.

"In the past, poor lens design led to complications with the AC IOLs, but the current flexible, open-loop models represent improved technology," said Dr. Steinert, professor of ophthalmology, University of California, Irvine. "Therefore, we have to consider whether the outcomes associated with use of modern AC IOLs are a reflection of the lens or their use in complex cases that are predisposed to higher rates of complications."

Anterior chamber IOLs

One clear advantage of AC IOLs is that they are easy to insert and involve a relatively short surgical time. In addition, there is a long-term track record available for the modern, open-loop AC IOLs and it demonstrates they offer long-term stability.

Nevertheless, sizing is an issue.

"These lenses are easy to insert, but hard to insert well," Dr. Steinert said.

Among the limitations of the AC IOLs is the requirement for the presence of a normal angle structure. In addition, the uveitis-glaucoma-hyphema (UGH) syndrome still occurs occasionally, and questions remain about whether use of AC IOLS is associated with an increased risk of cystoid macular edema (CME) and late corneal decompensation.

Trans-scleral-sutured PC IOLs

Dr. Steinert said from a theoretical perspective, one advantage of trans-scleral-sutured PC IOLs is that the ciliary sulcus is considered the second best location for IOL fixation after the capsule bag itself.

"It offers maximum separation from sensitive iris tissue and the corneal endothelium, avoids involvement of the angle or trabecular meshwork, and if the surgery is done well, results in no pupil distortion," he said.

Compared with AC IOL implantation, the surgery is technically challenging, takes more time, and involves more open eye time. The latter is a risk in itself, and other risks include hemorrhage if the anterior ciliary artery is cut by the needle, and endophthalmitis, because late suture exposure can occur and provide a route for microbial entry.

More recently, problems with late suture breakage and IOL dislocation have also been described.

Iris-sutured PC IOLs

This technique features all internal sutures so endophthalmitis is not an issue, and it has not been associated with reports of late suture breakage. Its use of a PC implant also might be considered an advantage because the PC IOL is perceived as having a better track record than an AC IOL.

Similar to the trans-scleral-sutured PC IOL, the drawbacks of the iris-sutured implant relate to the fact that it is technically challenging surgery involving increased surgeon and open eye time. Furthermore, because it requires adequate iris support, it is not an option for all patients. In addition, pupil distortion is common, and of the three techniques, it also has the shortest track record.

"There is limited information on iritis and cystoid macular edema (CME) with these IOLs," Dr. Steinert said. "We have to ask whether we need more follow-up to know more about the complications."

Reviewing the literature