Better results from primary AC vs. scleral-fixated IOLs in eyes with poor capsular support

Primary anterior chamber IOL implantation during cataract surgery in eyes with inadequate capsular support resulted in better visual outcomes than primary scleral fixation of IOLs, a retrospective study found.

Yoland Y. Y. Kwong, MRCSEd, and colleagues at the Chinese University of Hong Kong compared the visual outcomes in 46 eyes of 46 patients implanted with a Pharmacia 351C anterior chamber IOL to those in 36 eyes of 36 patients implanted with an Alcon CZ70BD posterior chamber scleral-fixated IOL. In all cases, the lenses were implanted during cataract surgeries complicated by loss of posterior capsule integrity. Phacoemulsification or extracapsular cataract extraction were used in all cases. Follow-up ranged from 6 months to more than 5 years.

Previous studies have compared outcomes between scleral-fixated and anterior chamber IOLs when implanted during secondary surgeries. The study by Dr. Kwong and colleagues focused on primary implantation in single, uninterrupted surgeries.

"Advantages of primary over secondary IOL implantation include the avoidance of a second operation, a short hospital stay, and a faster visual rehabilitation," the authors said.

At a mean 33 months' follow-up, logMAR visual acuity averaged 0.322 in eyes that received an anterior chamber IOL, significantly better than the scleral-fixated IOL group, which had a mean visual acuity of 0.486 (P = .01). In the anterior chamber IOL group, 71% of eyes achieved a Snellen visual acuity of 20/40 or better compared with 47.2% of eyes in the scleral-fixated IOL group.

No major adverse events occurred during lens insertion. Across both groups, transient postoperative corneal edema was the most common complication within 1 month postop, and an IOP greater than 22 mm Hg ws the most common complication after 1 month.

"Although both the number of eyes and the total number of complications were higher in the [scleral-fixated IOL] group, the differences were not statistically significant for early and late complications," the study authors said.

Because scleral fixation of an IOL takes longer to perform than anterior chamber IOL implantation, the authors speculate that prolonged phototoxicity from the operative microscope may have contributed to light-induced retinal injury in patients with scleral-fixated IOLs, and thus inferior visual results. Another explanation could be the occurrence of pseudophakic cystoid macular edema, the authors said, but the rate of this complication could not be measured in the study.

The study is published in the January issue of Ophthalmology.