Zigzag incision successful for femtosecond laser corneal transplantation

The femtosecond laser (IntraLase, Advanced Medical Optics) can create corneal incisions in a number of patterns, according to Roger Steinert, MD, of The Eye Institute, University of California Irvine. Hardware and software changes to the laser facilitate creation of perfectly matched donor and host incisions that interlock, resulting in watertight incisions with minimal suture tension and distortion, faster visual recovery with less astigmatism, and strong wound healing.

"The goal is to provide better quality of vision, faster recovery of vision, and stronger wound healing," Dr. Steinert said. "We are trying to achieve better alignment of the anterior surface, reduce rotational misalignment, reduce the impact of suture tension, and reduce the impact of postoperative wound healing."

Dr. Steinert compared the zigzag incision with the top hat incision, which has been found to have structural problems with the posterior phalange, which does not inherently fall into position and remain there, he explained. The shape of the incision eventually evolved to the zigzag shape that stays in position.

He demonstrated on optical coherence tomography that the zigzag incision allowed strong healing, there was no compression 1 month postoperatively, and there was accelerated strong stromal healing, which was never seen before, only healing in Bowman's membrane and Descemet's membrane, Dr. Steinert said.

Postoperative results in 13 eyes in which the zigzag incision was used showed that at 3 months nine of the 13 eyes had less than 3 D of cylinder. The visual acuity results were very good with seven of eight eyes.

"The femtosecond laser penetrating keratoplasty incision is feasible with improved results," he said. "There are low levels of astigmatism postoperatively and excellent best spectacle-corrected visual acuity. The zigzag configuration takes advantage of laser technology. The procedure is stable. More experience is needed with this procedure to validate the results."