Early zigzag-pattern PK results favorable

KOLOA, Hawaii — Early results of zigzag-pattern penetrating keratoplasty performed with a femtosecond laser show the procedure to improve postoperative outcomes, according to a presenter here.

The zigzag configuration, which can only be made with a femtosecond laser, "is biomechanically stable and secure and surgically straightforward," said Roger F. Steinert, MD, here at the Subspecialty Saturday meeting of Hawaiian Eye 2007. "The advantage of the zigzag PK is that the watertight seal gives a smooth transition," he said.

Dr. Steinert performed the zigzag PK procedure on 16 eyes with up to 9 months' follow-up with the IntraLase femtosecond laser (Intralase Corp.). He performed a 0.5-mm lamellar ring cut at a depth of 320 µm, with 45° angle and 24–bite 10-0 nylon running suture closure.

Topography showed that at 3 months, six out of eight eyes were at or under the 3.5 D SimK mean. Four out of five eyes showed a best corrected visual acuity of 20/40 to 20/80. Dr. Steinert noted that typically with conventional PK it takes 6 months to regain functional vision and with Descemet-stripping lamellar endokeratoplasty it normally takes 3 months.

Postoperative evaluation with the Visante OCT (Carl Zeiss Meditec) "shows strong healing, and it shows that at 3 months there is a greater signal at the wound, which may correlate with wound healing," Dr. Steinert said.

He said he is working with Carl Zeiss Meditec, maker of the Visante OCT, to digitize the image to verify if this is quantifiably indicative of wound healing.

He also noted that the OCT image indicated the procedure is an improvement over conventional methods.

"You can see in the image the suture is absolutely perfectly aligned, telling us biomechanically we're doing something right here," he said.

Dr. Steinert said the next step is a randomized prospective comparison of femtosecond PK with conventional PK.