Image-guided femtosecond cataract surgery enables accurate IOL centration

Precise design of the capsulotomy enhances effective lens position, optimizing visual acuity and predictability of refractive outcomes.

Stephen G. Slade

CHICAGO — If the focus of femtosecond cataract surgery is to improve the effectiveness of cataract surgery, then image-guided femtosecond laser does just that, a surgeon said.

Stephen G. Slade, MD, FACS, presented findings at Refractive Subspecialty Day preceding the joint meeting of the American Academy of Ophthalmology and the Middle East Africa Council of Ophthalmology held here from the first series of accommodating IOLs implanted with an image-guided femtosecond laser.

“Our best corrected visual acuity — we’re looking now at the spherical component — of these first 50 patients was excellent,” Dr. Slade said.

However, further research is needed for cataract surgery to match or exceed refractive surgery in terms of outcomes.

“We have a ways to go in cataract surgery to give people the same vision that they have been expecting and can get out of their laser surgery,” Dr. Slade said.

According to a MarketScope survey, about one-fourth of the 80,600 U.S. cataract surgeons consider themselves cataract-refractive surgeons, Dr. Slade said. Femtosecond laser technology may change the cataract surgeon profile.

“Perhaps the upside of all of this is that if you look at cataract surgery, not only are we not giving more effective results than excimer surgery, but we really don’t even think of ourselves as refractive surgeons,” he said.

“If we are going to give what our patients are expecting, we are going to need things to give us a better uncorrected visual acuity. I believe that this device, image-guided femtosecond laser technology, will be able to do that for us,” Dr. Slade said, adding that the utility of the laser is limited only by its programming.

Accurate capsulorrhexis and effective lens position

The study included 50 consecutive patients who underwent cataract surgery and IOL implantation with an image-guided LenSx femtosecond laser (Alcon).

Dr. Slade and colleagues used the image-guided laser to perform multiplanar corneal incisions, capsulorrhexes and lens fragmentations before implanting accommodating IOLs.

“Our purpose was to affect the effective lens position, to standardize this,” Dr. Slade said. “The effective lens position is the fudge factor of all of our IOL calculations. It is very important. It is a key, significant source of IOL power error and the capsulorrhexis directly affects that. A big capsulorrhexis will contract less, a smaller capsulorrhexis contracts more and an oval capsulorrhexis can asymmetrically contract, inducing aberrations and even astigmatism to the eye.”

Femtosecond technology enables far more predictable capsulorrhexis design and effective lens position than manual techniques, Dr. Slade said.

“You simply cannot do a manual capsulotomy as well as you can with the laser,” he said. “We looked at our variability of the lens position, looking at IOLs done both with the femtosecond-guided device vs. manual, and by 1 month we had a tighter standard deviation with the femtosecond-guided laser.”

Results showed that the femtosecond procedure optimized visual outcomes, with 92% of eyes having best corrected visual acuity of 20/30 or better at 1 day after surgery and 100% of eyes having BCVA of 20/30 or better at 1 week. – by Matt Hasson

• Stephen G. Slade, MD, can be reached at Slade & Baker Vision, 3900 Essex Lane, Suite 101, Houston, TX 77027; 713-626-5544; fax: 713-626-7744; e-mail: sgs@visiontexas.com.
• Disclosure: Dr. Slade is a consultant for Alcon.

As a co-inventor of optical coherence tomography, I am gratified to see another major application for OCT-guided surgery. It combines the precision of femtosecond laser and OCT to accurately locate and cut the anterior capsulorrhexis, fragment the nucleus and create a protective plate of posterior epinucleus to decrease the chance of posterior capsule rupture. This will make the surgery safer and more exact, paving the way for more widespread use of accommodating and multifocal intraocular lenses. Despite my enthusiasm for the technology, it remains to be seen whether femtosecond laser cataract surgery makes sense economically. The levels of allowable payment and reimbursement have yet to be set. I think this will determine the popularity and speed of adoption of this new technology in the near future.

– David Huang, MD, PhD
Weeks Professor of Ophthalmic Research, Casey Eye Institute, Oregon Health & Science University

The take-home message of this study is that precision imaging (OCT or 3-D confocal structured illumination) coupled with a precision cutting tool (femtosecond laser) can enhance the way we do surgery, especially refractive cataract surgery, in which a specific refractive outcome is desired. With the advent of premium channel IOLs to enhance the refractive outcomes of patients desiring “glasses free” vision, the accuracy of effective IOL position and centration has become critical in meeting this endpoint. We have seen major advances in the optical refinement of IOLs and in the IOL power calculations, while the surgical procedure itself has only seen smaller incremental improvement since the advent of phacoemulsification several decades ago. An image-guided femtosecond laser represents a major advance in the surgical procedure and offers the potential for an ideal capsulotomy size, shape and centration every time and enhanced safety in performing nucleus fragmentation. Few individuals would criticize the safety and surgical precision of this technology. Rather, the question some might have is regarding cost and reimbursement. We look forward to the implementation of this technology in the market and how the market dynamics will answer the question of cost and reimbursement.

— Ronald R. Krueger, MD
Cleveland
Disclosure: Dr. Krueger is a consultant for Alcon.