Inverse mushroom-shaped nonmechanical penetrating keratoplasty using a femtosecond laser

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 polymethyl methacrylate (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 μ m) 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." © 2005 by Elsevier Inc. All rights reserved.