[Experimental studies of the precision of lamellar corneal sections]

Using an automatic rotating microkeratome for lamellar corneal grafting, 200 porcine corneal specimens were subjected to lamellar dissection. The aim of the study was to define the factors influencing the optimal thickness of the corneal lamella. The factors investigated were: the rotation speed of the trephine blade; the speed of blade advancement; the influence of lubrication fluids; intraocular pressure; geometry of the rotating blade. Ultrasound pachymetry was performed on non-fixed tissue in 13 defined positions. The optimal conditions for lamellar dissection with the rotating microkeratome were found to be a speed of 0.5 mm/s blade advancement, an intraocular pressure of 40 mmHg, lubrication of the cut area with a 0.05% Healon/BSS +/- solution. Under these conditions the thickness of the lenticule showed an inhomogenity of 2.5% total thickness, which was located in the direction of blade advancement and blade rotation speed.