Inverse Mushroom-shaped Nonmechanical Penetrating Keratoplasty Using a Femtosecond Laser

To demonstrate the feasibility of an inverse mushroom-shaped nonmechanical corneal trephination using a femtosecond laser in a noncontact manner. Experimental study. 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. 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 μm) with tissue bridges in between. By TEM, the cut edges were lined by a delicate, electron-dense layer (5–40 nm). Femtosecond laser technology seems to offer a promising approach towards minimally invasive self-sealing “no-stitch keratoplasty.”