Noncontact trephination of the cornea using a pulsed hydrogen fluoride laser.

We used a pulsed hydrogen fluoride infrared laser and a specially designed axicon lens to perform circular corneal trephinations in ten eye bank eyes. This noncontact system focused each laser pulse into an annulus on the cornea. Corneal perforation was achieved in seven to nine seconds at a repetition rate of 10 Hz, using a laser output energy of 100 mJ per pulse. A trephination, 90% of corneal thickness, 6.5 mm in diameter, was produced with 70 pulses.