Three phakic IOLs do not produce anatomic distortions

November 1, 2007

A study using optical coherence tomography (Visante, Carl Zeiss Meditec) found that a single-piece acrylic, hydrophobic phakic IOL (AcrySof phakic IOL, Alcon Laboratories); a single-piece, hydrophilic acrylic IOL (ICare IOL, Corneal); and a newer, trimmed version of the latter (ICare Evolution IOL, Corneal) did not produce anatomic distortion of the iris or the chamber angle. The study compared angle-to-angle distances ≥6 months after lens implantation.

Key Points

Verona, Italy-Three phakic IOLs did not produce anatomic distortion of the iris or chamber angle, as evidenced by optical coherence tomography ([OCT]; Visante, Carl Zeiss Meditec) that was used to compare angle-to-angle distances ≥6 months after lens implantation in a recent study.

"We planned a study to gain an understanding of the sizing, vaulting, the distance between the optical plate of the IOL and the endothelial cells, and the ongoing distortion caused by that distance in the eye," said study co-author Simonetta Morselli, MD. She is director of anterior segment surgery at the Hospital Ophthalmic Unit, Verona, Italy.

Dr. Morselli and co-author Roberto Bellucci, MD, conducted the study in which a single-piece acrylic, hydrophobic phakic IOL (AcrySof phakic IOL, Alcon Laboratories), which is in FDA trials, was implanted into 10 eyes. Ten more eyes received a single-piece, hydrophilic acrylic IOL (ICare IOL, Corneal), and another 10 received a newer, trimmed version of the latter (ICare Evolution IOL, Corneal), which has less folding and a reduced number of foot plates.

The investigators measured the distance from the posterior optical plate of the IOL and the crystalline lens. In addition, they attempted to determine whether there was distortion in the anterior chamber angle or occlusion of the angle by the IOL haptics.

"With the [hydrophobic IOL], we found that there was very good clearance between the optical plate and the endothelial cells," she said. There was less clearance with the other two IOLs.

Vaulting was evaluated in all three IOLs to determine the orientation to the anterior chamber angle. "We found a low clearance with the older [hydrophilic acrylic] design. Three IOLs were explanted due to loss of the endothelial cells and formation of a cataract. We found good results with the [hydrophobic acrylic] and the [newer hydrophilic acrylic IOL]," she said.

Results showed that corneal clearance was low with the older-design hydrophilic acrylic IOL but was more than adequate with the other two IOLs. The difference was not significant.

She and Dr. Bellucci praised the ability of OCT in evaluating lenses intraocularly. OCT is helpful to measure the diameter of the anterior chamber to ensure proper IOL length, decentration and tilting, vaulting, and corneal clearance, they said.

"The study of phakic IOLs did not produce any anatomic distortion of the eyes or the chamber angle. OCT is a helpful instrument to study the eyes that are candidates for IOL implantation and vaulting preoperatively and postoperatively," she said.