gms | German Medical Science

The postoperative clinical course after penetrating keratoplasty and trephination in free form using a guided Excimer-laser beam has been published before. Now, the findings of light-microscopy comparing corneal wound healing after laser trephination and conventional trephination with a motor trephine in the rabbit model are presented.

Homologous penetrating keratoplasty was performed on 12 NZW rabbits (6 animals with mechanical trephination, 6 animals with Excimer-laser trephination). The cutting edges achieved by both trephination techniques were examined by light and scanning-electron microscopy. Corneal wound healing was evaluated by light-microscopy of corneal specimen retrieved from animals that were killed after 3 and 6 weeks and after 6 months, respectively.

The cutting edges of corneal incisions with the Excimer-laser demonstrated the known precision with only minimal collateral damage to adjacent tissue structures. In both trephination groups, corneal specimens could be retrieved for histological evaluation at all scheduled dates. There were no significant differences regarding the wound healing process between the two trephination groups. After 6 months corneal specimen of both groups demonstrated complete healing. Corneal thickness in the wound areas did not differ significantly from the normal corneal tissue.

Experimental follow-up studies to evaluate the feasibility of the developed technology of laser-trephination in the living eye had shown no differences between conventional mechanical and Excimer-laser trephination with a guided beam. The present histology study neither demonstrates any significant differences in corneal wound healing between the two trephination groups. Thus, Excimer-laser trephination in free form appears to be a valuable addition to the surgical repertoire in the presence of selected corneal pathologies.