CLINICAL ANALYSIS OF THE NEODYMIUM-YLF PICOSECOND LASER AS A MICROKERATOME FOR LASER IN-SITU KERATOMILEUSIS - PARTIALLY SIGHTED EYE STUDY

Purpose: To evaluate the use of a picosecond neodymium:YLF (Nd:YLF) la ser as a nonmechanical intrastromal microkeratome. Setting: Universita Cattolica del Sacro Cuore, Rome, Italy. Methods: An intrastromal spir al disc pattern of picosecond laser pulses was used to create a cornea l flap for laser in situ keratomileusis (LASIK) in 14 partially signed eyes. Results: Flaps with a 6.0 mm diameter and 180 to 200 mu M depth were successfully created in most cases. The underlying stroma was tr eated with a Lambda Physik excimer laser using a 3.5 to 4.5 mm optical zone. Patients were divided into 8 groups for target corrections of 5 .0, 10.0, and 15.0 diopters of myopia. Good corneal clarity and refrac tive undercorrection were recorded in each group 6 months postoperativ ely. The undercorrection was due in part to the limited optical zone o f the laser's delivery system. Sone flap decentration was notes. Concl usion: This pilot study indicates that the Nd:YLF picosecond laser may be clinically applied for creating corneal flaps for LASIK. Further r efinements of the laser delivery system will include enlargement of th e flap diameter and improvements in flap centration. The use of a fema tosecond laser may expand the capabilities and precision of this techn ology.