Femtosecond laser enables safe, reproducible cataract surgery

Accurate capsulotomy, efficient lens fragmentation and reduced phaco power enhance clinical outcomes.

A new femtosecond laser platform proved safe and effective for cataract surgery, according to a physician at OSN New York 2009.

Femtosecond laser technology can be used to make incisions, soften the crystalline lens and perform capsulotomy, according to Richard L. Lindstrom, MD, OSN Chief Medical Editor. He reviewed early results of a study by Hungarian surgeon Zoltan Nagy, MD, on use of the LenSx femtosecond laser (LenSx Lasers) for cataract surgery. Several companies are working on similar technology, he said.

“This is going to provide cataract surgeons with a whole new way of doing cataract surgery, coming down the pike probably in about the next 12 months,” Dr. Lindstrom said. “It looks like this femtosecond laser is going to be as important to cataract surgeons as it has been to the LASIK surgeons.”

Current surgical methods offer poor surgeon-to-surgeon and case-to-case reproducibility, he said. Femtosecond laser technology promises to enhance the reproducibility of cataract surgery and enable more precise lens treatment, capsulotomy and incision creation than existing manual methods, Dr. Lindstrom said.

“What can a femtosecond laser do for us?” he said. “Well, it can actually soften the lens. … It can create a perfectly sized and centered refractive capsulotomy. It can do the surgical incisions. And it can also basically create a limbal relaxing incision or corneal relaxing incision.”

Safe, precise capsulotomy

Femtosecond laser technology can be used to create a perfectly centered, shaped and sized refractive capsulotomy, Dr. Lindstrom said.

An arm of Dr. Nagy’s study focusing on capsulotomy included 60 patients who underwent laser capsulotomy and 60 patients who had manual capsulorrhexis. Results showed that laser capsulotomy yielded perfect centration, precise diameter, and easy, complete removal of the capsule, with no radial tears or other adverse events, he said.

The LenSx platform enhanced capsulotomy diameter accuracy. Only 20% of manual capsulorrhexis procedures were within 0.25 mm of the targeted diameter, Dr. Lindstrom said.

“He is able to do that with the capsulotomy with the femtosecond laser,” he said. “We pride ourselves for being pretty good and making these capsulotomies, but it’s pretty tough to make it that perfect.”

Scanning electron microscopy showed capsulotomy performed with the femtosecond laser also proved safer and more accurate than manual techniques in a group of porcine eyes, he said.

“It looks like the femtosecond laser capsulotomy is actually more resistant to radial tears than those done with a capsulorrhexis forceps or with a needle,” Dr. Lindstrom said.

Lens fragmentation techniques

An arm of Dr. Nagy’s study addressing lens treatment included 61 patients who underwent laser treatment and phacoemulsification and 54 patients who had phacoemulsification only. In the laser group, 26 patients had softer lenses and 35 patients had harder lenses. Phaco power and time were recorded for 21 patients in that group.

In eyes with softer lenses, femtosecond laser energy was applied in a cylindrical pattern, which proved effective in liquifying the lenses. In eyes with harder lenses, power was applied in a cross pattern, which fragmented the lenses and eliminated the need to sculpt them.

Differences in phaco power and effective phaco time between the 21 laser-phaco patients and the phaco-only patients were statistically significant, suggesting an improvement in safety, Dr. Lindstrom said.

Easier incisions, lens implantation

The femtosecond laser will also help cataract surgeons perform limbal and corneal relaxing incisions for astigmatism correction, Dr. Lindstrom said.

“Only about 25% of cataract surgeons have easy access to an excimer laser and are comfortable using it,” he said. “One of the barriers to premium IOLs, particularly presbyopia-correcting IOLs, is nervousness and inability to enhance. But they aren’t comfortable with LASIK and at the slit lamp making a corneal relaxing incision.”

Femtosecond laser technology will also help surgeons improve outcomes of premium IOL implantation, he said.

“That’s really going to enhance the outcome, I think, of accommodating lenses, particularly the Synchrony, which will require a continuous center cut that is just right,” he said.

More data from Dr. Nagy’s study are forthcoming. – by Matt Hasson

• Richard L. Lindstrom, MD, can be reached at Minnesota Eye Consultants, 9801 DuPont Ave. S., Suite 200, Bloomington, MN 55431; 952-888-5800; fax: 952-567-6182; e-mail: rllindstrom@mneye.com. Dr. Lindstrom is a consultant and investor for LenSx.