The recipient and donor trephinations were performed from the epithelial side using either a motor trephine ( Microkeratron , Geuder , n = 91 ) or an 193-nm excimer laser ( MEL60 , Aesculap-Meditec , 1.5 x 1.5 mm spot mode , 16 - 24 mJ/pulse , repetition rate 25/s ) along round metal masks with 8 `` orientation teeth/notches '' ( n = 88 ) .
