Inverse mushroom-shaped nonmechanical penetrating keratoplasty using a femtosecond laser

Abstract

Purpose: To demonstrate the feasibility of an inverse mushroom-shaped nonmechanical corneal trephination using a femtosecond laser in a noncontact manner.

Design: Experimental study.

Methods: In this laboratory study, 10 polymethylmethacrylate (PMMA) blocks and 20 porcine corneas were treated with an industrial femtosecond laser source. The trephination profile consisted of (1) a 7- or 6-mm diameter cylinder from the anterior chamber, (2) an intermediate horizontal connecting plane, and (3) a concentric 5- or 4-mm diameter cylinder upwards.

Results: Applying appropriate combinations of pulse energy and spacing, trephination took less than 60 seconds. In porcine eyes, light microscopy displayed trephination edges delineated by partly confluent gas bubbles (10-40 mum) with tissue bridges in between. By TEM, the cut edges were lined by a delicate, electron-dense layer (5-40 nm).

Conclusions: Femtosecond laser technology seems to offer a promising approach towards minimally invasive self-sealing "no-stitch keratoplasty."