Reducing femtosecond laser complications

Budapest, Hungary-Early problems associated with femtosecond laser-assisted refractive cataract surgery have been successfully downsized thanks to ongoing platform improvements and the introduction of new surgical instruments and techniques.

However, surgeons should understand that it is a different procedure than conventional cataract surgery and thus must be prepared to recognize and manage potential complications, said Zoltán Z. Nagy, MD, PhD, professor of ophthalmology, Semmelweis University, Budapest, Hungary.

Complications were generally limited to the learning curve period and mostly involved capsulotomy adhesions, which could lead to anterior capsular tears, said Dr. Nagy, who was believed to be the first to perform femtosecond laser-assisted cataract surgery in 2009.

However, with the platform Dr. Nagy used (LenSx, Alcon Laboratories) a free-floating capsulotomy was achieved in 95% to 96% of patients, thanks to the advent of high-definition optical coherence tomography (OCT) guidance and implementation of a new patient interface (SoftFit).

Should the capsulotomy be incomplete, it can be identified by the presence of trapped gas bubbles underneath the anterior capsulotomy, said Dr. Nagy

“In this situation, surgeons should follow the contour of the capsulotomy using a rhexis forceps to avoid causing an anterior capsule tear,” he said.

Proper insertion of the patient interface, Dr. Nagy said, is important not only for achieving a free-floating capsulotomy, but also to minimize any surgically induced astigmatism and lens tilt.

“The insertion should be as central as possible,” he said. “Achieving this goal is much easier using the new patient interface . . . as it also provides a larger surgical field and reduces IOP elevation.”

Capsular block syndrome leading to posterior capsule rupture has also been described in femtosecond laser-assisted cataract surgery. However, the risk can be minimized by performing a gentle hydrodissection and manipulating the nucleus with a rock-and-roll technique.

During gentle hydrodissection, Dr. Nagy said, the surgeon should move the lens up and down and turn it around, but only a bit as these maneuvers help the intralenticular gas to come forward into the anterior chamber and leave the eye.

“If the capsulotomy is irregular, the chance of propagating a rupture toward the posterior capsule will be higher using any technique,” he said. “Therefore achieving a regular, circular capsulotomy is key and using a femtosecond laser to create the capsulotomy helps in this respect.”

With OCT guidance to maintain a safe distance from the posterior chamber, there have never been complications associated with the lens liquefaction step, according to Dr. Nagy.

However, use of a special chopper designed by Dr. Nagy-which will be introduced by ASICO-can help lower the amount of phacoemulsification energy used.

In opening femtosecond laser-created corneal incisions, Dr. Nagy said using a special thin, blunt-tipped spatula makes the task easier than using thicker traditional spaturals to open the main wound after filling the anterior chamber with viscoelastic to open the side-port incisions.

“The length of the main incision should not exceed 1.8 mm to minimize surgically induced astigmatism and it should be as peripheral as possible,” he said.

A special chopper also helps to fragment the nucleus along the fragmentation lines created by the femtolaser, he said.

Dr. Nagy is a consultant to Alcon Laboratories.

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