Femtosecond laser has multiple surgical capabilities

October 15, 2009

The femtosecond laser has capabilities for enabling and improving additional surgical maneuvers.

This device, however, also has capabilities for enabling and improving additional surgical maneuvers, and other manufacturers, including Abbott Medical Optics, LensAR, and OptiMedica, are developing femtosecond lasers for use as multitasking tools in cataract surgery as well.

"For over 40 years since the advent of small-incision phaco by Charles Kelman, MD, many of the important aspects of cataract surgery have been performed manually with the possibility of imprecision and even complications," said William W. Culbertson, MD, at the annual meeting of the European Society of Cataract and Refractive Surgeons (ESCRS). "In recent years, engineers, scientists, physicists, and ophthalmologists have been collaborating to develop the femtosecond laser to improve these steps.

In the same ESCRS session, Zoltan Nagy, MD, professor of ophthalmology, Semmelweis University, Budapest, Hungary, described use of the femtosecond laser from LenSx Lasers for performing capsulorhexis and to create corneal incisions and soften the nucleus to enable aspiration.

For the study with the femtosecond laser in development by OptiMedica, proprietary treatment-planning software allowed the surgeon to design the capsulotomy diameter and the depth and pattern of nuclear segmentation. Then, real-time optical coherence tomography (OCT) was used for guidance at the time of the procedure. The study population comprised 20 sighted human eyes with grade 2 to 4 nuclear cataracts and no anterior segment pathology.

The laser was used to create 5-, 5.5-, and 6-mm capsulotomies and to perform four-quadrant nuclear segmentation and four-quadrant nuclear softening on harder lenses. In all eyes, the capsulorhexis was within 0.1 mm of the intended size, Dr. Culbertson said.

"The capsulotomy edge was without defects and smooth, very similar to what we would see in a manually created capsulorhexis," he said. The four-quadrant nuclear segmentations were performed with predetermined diameters ranging from 4.5 to 6 mm and by cutting from the bottom up. Initially they were started at 80% nuclear depth, but as confidence increased, the depth was increased to 90%, leaving a 500-µm lens cushion.

Dr. Culbertson reported the presegmentation facilitated quadrant separation, and nuclear softening facilitated rapid phaco-assisted nucleus aspiration. "Use of the femtosecond laser essentially converted a grade 4 nuclear cataract into a grade 2 nuclear cataract so that we were often able to turn off the longitudinal phaco and just use the torsional mode," he said.