Endothelial graft interface analysis shows disorganized collagen patterns induced by femtosecond laser

PARIS — Structural modifications induced in the posterior stromal collagen by the laser may explain the poorer visual results of femtosecond laser-assisted endothelial keratoplasty compared with mechanical methods, according to a study.

During the SFO-EVER symposium at the meeting of the French Society of Ophthalmology, Jean-Louis Bourges, MD, PhD, presented the results of in vivo confocal microscopy performed on femtosecond laser-assisted endothelial keratoplasty grafts in 26 patients. Electron microscopy was used for further observation on histological specimens of explanted grafts in four patients who needed conversion.

Jean-Louis Bourges

“The interface fibrosis presented an abnormal, disorganized, disoriented pattern of the collagen fibers, which is likely to result in poor optical quality due to loss of transparency and aberrations,” Bourges said.

He said that this perturbation of collagen structure is not found in femtosecond-cut LASIK flaps nor in anterior lamellar grafts, probably due to the different response of the anterior stroma to the laser.

“Hopefully, we will be able to improve the technique by modification of the laser parameters, but there is a chance that the laser itself has a negative interaction with the stromal collagen at the endothelial level,” he said.

He suggested going back to preclinical studies to better understand the tissue reaction to the laser.

This technique has a lot of potential advantages, and we need to study it further. At this stage, however, we should not use it in patients who have the potential to recover visual acuity by endothelial keratoplasty,” he said.

Disclosure: Bourges has no relevant financial disclosures.