Round anterior optic edged-IOL more superior

Salt Lake City-IOLs with round anterior optic edges are more suitable than those with anterior and posterior square optic edges for sulcus fixation, according to recent study results presented by Liliana Werner, MD, PhD.

“In cases of posterior capsule rupture during cataract surgery, surgeons can fixate an IOL in the sulcus provided there is still peripheral capsular support, and usually a 3-piece lens with rounded anterior optic edges is indicated in these cases,” said Dr. Werner, associate professor of ophthalmology and co-director of the Intermountain Ocular Research Center at the John A. Moran Eye Center, University of Utah, Salt Lake City.

“However, in a review of the literature, there appears to be no formal study that compared 3-piece foldable IOLs having square versus round anterior optic edges,” she said. “To our knowledge, this is the first comparative pathologic study evaluating these two groups of lenses, and the results suggest that a 3-piece lens with round edges on the anterior optic surface is really more suitable for sulcus fixation in cases of complicated surgery.”

The pathologic comparison study-which evaluated pseudophakic postmortem eyes-was done using cadaver eyes obtained from eye banks, and information on IOL implantation date was received through interaction with the eye donor’s family.

The eyes were fixated in formalin, and then IOL fixation, tilt, and decentration were evaluated by imaging with high-frequency ultrasound and MRI. Next, eyes were bisected for gross examination of the anterior segment from a posterior view.

A total of 13 eyes were identified with a hydrophobic acrylic 3-piece IOL with square anterior/posterior optic edges. There were 14 eyes with 3-piece IOLs with round anterior optic edges, of which 13 were silicone and 1 was hydrophobic acrylic.

Gross examination of the eyes showed nearly all had complicated surgery with posterior capsule rupture.

The two groups were comparable for decentration, tilt, pigmentary dispersion, and transillumination defects. However, histopathology findings were much more prominent in the group of 3-piece lenses with an anterior square optic edge, particularly with regard to the presence of pigment in the trabecular meshwork, Dr. Werner said.

“This indicates the trauma in these eyes was not limited to the complicated surgery, but there was continuous trauma to the posterior surface of the iris that is likely related to rubbing by the square optic edge,” she said. “In both groups, the pathologic signs were more prominent in eyes where the IOL was asymmetrically fixated and were mostly seen on the side of the lens fixated in the sulcus.”

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