Post-LASIK ectasia concern may dwindle

STOCKHOLM, Sweden — Post-LASIK ectasia is not a major concern if guidelines are followed and an accurate analysis of preoperative topography and wavefront data is performed, according to a panel of surgeons here.

Presenting a retrospective review of 140 high myopic patients operated in the early years of LASIK over a period of up to 20 years, Patrick Condon, MD, said that despite the relatively greater risk of high myopia, ectasia can be a minor problem.

"Only one patient with a thicker than anticipated flap and therefore a residual stromal bed of only 120 µm developed ectasia," Dr. Condon said here at the European Society of Cataract and Refractive Surgeons. "In all the other cases, where residual stromal bed was within the safety limits, there was no sign of this complication."

In another retrospective review of the 22 cases of post-LASIK keratectasia followed in the Eye Clinic of Bordeaux, the risk factors that were potentially at the origin of this complication were examined.

"Topographic abnormalities, like keratoconus, form fruste keratoconus and pellucid marginal degeneration, were found in 14 cases," Julien Kerauret, MD, said. "High myopia, in connection with astigmatism or dry eye, was observed in four cases. Predicted residual stromal bed was less than 249 µm in one case."

In all the cases in which preoperative topographies were available, a pre-ectatic condition was always present, he noted.

As Michael Knorz, MD, said, "This analysis demonstrates that in most cases post-LASIK ectasia could be prevented by accurate analysis of topographic data."

Together with Antonio Marinho, MD, he recommended the use of all available technologies for preoperative evaluation of the cornea.

"Form fruste keratoconus remains the most important risk factor to be considered," Dr. Marinho said.

When post-LASIK ectasia develops without any apparent risk factor, surgery-induced oxidative stress should be considered as a potential cause, according to Nataliya Maychuk, MD.