Real-time optical coherence tomography guidance optimizes cataract surgery

August 15, 2010

Experience using a proprietary femtosecond laser with an integrated, real-time optical coherence tomography imaging device highlights the advantages provided by this technology in performing cataract surgery and its potential to raise the bar for functional and safety outcomes.

Boston-Experience using a proprietary femtosecond laser (LenSx, LenSx Lasers/Alcon Laboratories) with an integrated, real-time optical coherence tomography (OCT) imaging device highlights the advantages provided by this technology in performing cataract surgery and its potential to raise the bar for functional and safety outcomes, said Zoltán Nagy, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery.

Dr. Nagy presented a video to demonstrate cataract surgery performed using the OCT-guided femtosecond laser platform for anterior capsulotomy, lens fragmentation, and to create multiplanar, self-sealing corneal incisions.

In addition, he reported findings from clinical studies showing statistically significant superiority of results in procedures performed using the femtosecond laser system compared with conventional manual techniques in terms of improved surgical efficiency and IOL centration.

He explained that the OCT images are captured rapidly with the eye fixed and applanated in its surgical position with the patient lying in a supine position. The delivered laser surgical pattern is computer-guided, but the surgeon has complete control in terms of on-the-fly ability to modify the parameters at any time using an intuitive touch-and-select software interface.

To use the OCT-guided femtosecond laser system, the surgeon centers the corneal incisions, capsulotomy, and lens fragmentation pattern. Then, the capsule position and corneal thickness are determined based on cross-sectional OCT images. The OCT guidance assures that the laser pattern for lens fragmentation is delivered at a safe distance from the anterior and posterior capsule and that the capsulotomy is centered precisely and cuts completely through the anterior capsule.

The lens fragmentation/liquefaction is performed first, then the capsulotomy, and finally the corneal incisions. The entire sequence is completed in about 60 seconds.

"We have also investigated performing the capsulotomy first, followed by lens liquefaction," he said. "While this order may have some advantages, there are also potential drawbacks, such as gas bubbles in the anterior chamber that could block lens treatment."

Proof of principle

Clinical study results show that the theoretical advantages of femtosecond laser cataract surgery translate into real benefits.

"These features translate into better visual outcomes and the potential to reduce posterior capsule opacification development," Dr. Nagy said.

Multivariate analyses were performed that showed IOL decentration was associated with irregularity of the capsulorhexis shape.

"With an irregular capsulotomy, there may be asymmetric vector forces as the capsule contracts that may play a role in IOL centration," Dr. Nagy concluded.

FYI

Zoltán Nagy, MD
E-mail: zoltan.nagy100@gmail.com
or nz@szem1.sote.hu

Dr. Nagy is a consultant to LenSx Lasers.