Femtosecond Laser Cataract Surgery: Advantages Await Clinical Trial Results

James Brice


November 26, 2012

In This Article

Key Study Needed for Femtosecond Laser Cataract Surgery

One of medicine's most intriguing new surgical technologies to treat one of the world's largest public health problems is reaching few patients, because key research confirming its clinical efficacy and outcomes may be years away from publication.

Femtosecond lasers promise to literally to cut a new edge in terms of the precision and accuracy of incisions made during cataract surgery, according to Calvin Roberts, MD, chief medical officer of Bausch + Lomb. Bausch + Lomb is 1 of 5 companies that produce US Food and Drug Administration-cleared femtosecond laser surgical systems.

Surgery using handheld instruments is the current standard for treating cataracts, which are responsible for nearly 50% of blindness worldwide. The success of this approach depends to a great extent on the surgeon's skill and experience. About 10 million cataract surgeries are performed annually worldwide, according to the World Health Organization.[1] Many of those patients could benefit from a conversion to femtosecond lasers guided by ultra-high-resolution 3-dimensional optical coherence tomography (OCT).

Femtosecond lasers are well suited for cataract surgery because of their ability to tightly focus energy to produce precise surgical incisions, Dr. Roberts said. Cuts of a uniform depth into the lens are possible. The disruptive heat associated with current laser technology is reduced as the laser pulses once every one-trillionth of a second. The ability to focus such energy allows the surgeon to cut deeply on a single plane without collateral damage, he said.

Results of preliminary research are promising. Femtosecond lasers produce continuous anterior incisions for capsulorrhexis that are twice as strong and more than 5 times as precise in size and shape as manual incisions, according a 2010 study by Palanker and colleagues[2] at Stanford University School of Medicine, Stanford, California.

Palanker and colleagues' research revealed that segmenting and softening the lens with a femtosecond laser simplifies its emulsification and removal. Three-dimensional cutting of the cornea takes advantage of internal pressure in the eye to create self-sealing incisions, and it allows exact placement of the limbal-relaxing incisions, often performed in the same procedure, that are used to treat astigmatism.

Friedman and colleagues,[3] also at Stanford University School of Medicine, measured the accuracy of an OCT-guided femtosecond laser for cutting specified circles and curved incisions and compared it with manually created capsulorhexis in a small human study. Deviation from the intended diameter of the resected capsule disk was 29 (± 26 μm) for the laser technique and 337 μm (± 258 μm) for manual incisions. Mean deviations from circularity were 6% for the laser and 20% for manual incisions.

The advantage conferred by this precision can be applied to corneal incisions, anterior capsulotomy, and lens softening and fragmentation before aspiration, noted Roger F. Steinert, MD, chair of ophthalmology at the University of California, Irvine, School of Medicine. "You can't do these things repeatedly or dependably when you are operating manually with a blade," he said.