Presbyopic intraocular lens surgery enhanced

September 15, 2010

Laser vision correction is an effective technique for improving the results of presbyopic IOL surgery, according to one expert.

"Use of presbyopic IOLs is increasing, and expectations for excellent outcomes are very high among patients who receive these implants," said Dr. Hardten, adjunct associate professor of ophthalmology, University of Minnesota, Minneapolis. "Most of the time, using careful biometry and relaxing incisions intraoperatively, surgeons can achieve the targeted refractive error and reduce pre-existing astigmatism.

"However, residual refractive error continues to be the most common reason for patient dissatisfaction with presbyopic IOLs," he said.

Before the enhancement procedure, mean distance uncorrected visual acuity (UCVA) was 20/46. Both hyperopic and myopic errors were present in the group. Mean absolute spherical equivalent (SE) was 0.98 ± 0.82 D and mean astigmatism was 1.33 ± 0.90 D.

"For most of our patients, reduction of astigmatism was the main goal for treating residual refractive error," Dr. Hardten said.

Standard LASIK accounted for 44 (75%) of 59 enhancement procedures and customized LASIK was performed in seven eyes (12%). Three eyes had standard PRK, three eyes had custom PRK, and two eyes had customized LASIK after lifting a precut LASIK flap.

"Although a custom ablation can provide better astigmatic and higher-order aberration correction, an accurate wavefront may be difficult to capture in eyes with a presbyopic IOL," Dr. Hardten said. "Therefore, it is always important to check for agreement between the manifest and wavefront refraction.

"As shown in this series where about 80% of the enhancements involved a standard ablation, wavefront-guided ablation is performed in only a minority of eyes with a presbyopic IOL," he said. "In addition, because our overall enhancement rate is low-only about 10% of our presbyopic IOL eyes need further treatment for residual refractive error-we do not routinely cut a flap before the IOL surgery."

All eyes in the series had at least 3 months follow-up after the enhancement procedure. The mean follow-up duration was 12.2 months overall and 10.9 months for the subgroup of 26 eyes with a multifocal IOL.

Excimer laser enhancement was effective in significantly reducing residual refractive errors. At last follow-up, mean SE was –0.18 D ±0.52 D and mean astigmatism was 0.41 ±0.42 D.

Similarly good outcomes were achieved in a subgroup analysis of the 26 eyes with a multifocal IOL. The pre-laser vision correction mean absolute SE for this group was 0.74 D and mean astigmatism was 1.15 D. At last follow-up, mean SE was 0.01 ±0.34 D and mean astigmatism was 0.23 ±0.2 D.

Analysis of the monocular UCVA in all eyes showed about 60% of eyes achieved at least simultaneous 20/40 at distance and J5 at near. Yet, as expected, when looking at the monocular UCVA in eyes with multifocal IOLs, the UCVA outcome improved to 80% of eyes achieving at least simultaneous 20/30 at distance and J3 at near.

Safety was good, with no eyes losing more than 1 line of best-corrected visual acuity (BCVA).

"When there was this mild BCVA loss, the reason was thought to be dryness early after the procedure, with improvement over time in eyes with longer follow-up," Dr. Hardten said.