Abstract
Abstract: :
Purpose: Automated lamellar keratoplasty requires conservation of the entire eye until the corneal lamellae can be cut by means of a microkeratome. In this study we have investigated the quality of corneal flaps for lamellar keratoplasty using different preparation regimes. Methods: Corneal lamellae were cut from porcine eyes using a Carriazo–Pendular microkeratome with 140 µm cutting depth (Schwind, Eyetech solutions, Germany). Five corneae were cut from fresh enucleated porcine eyes without any preparation. Five after rising intraocular pressure up to 30 mmHg with an intravitreal needle passing through the optic nerve. Five were cut after crosslinking the cornea with riboflavin and an UV–lightsource and five more with increased IOP to 30 mmHg. Finally five more eyes were stored at 4 °C in Optisol medium for one day and then cut with IOP at 30 mmHg. The corneal lamellae were examined regarding thickness, stromal integrity –estimated by light microscopy– and surface quality using scanning electron microscopy. Results: The fresh enucleated eyes with IOP of 30 mmHg showed the best results regarding the mentioned quality parameters. The thickness was closest to the intended cutting depth and surface showed the highest quality of all. In addition stromal integrity seemed to be best with these samples. Conclusions: For controlled cutting conditions in automated lamellar keratoplasty the microkeratome requires the entire eyebulb in order to place the suction ring correctly. In this study only fresh enucleated porcine eyes with augmented intraocular pressure to 30 mmhg yield the intended results. Eyes without intraocular pressure did not allow to put the suction ring in a reproducible way. Further studies are set to establish clinical parameters for lamellae extractions at human eyebank eyes.
Keywords: transplantation • cornea: clinical science