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 picosecond neodymium:YLF (Nd:YLF) laser as a nonmechanical intrastromal microkeratome. Setting: Universita Cattolica del Sacro Cuore, Rome, Italy. Methods: An intrastromal spiral disc pattern of picosecond laser pulses was used to create a corneal flap for laser in situ keratomileusis (LASIK) in 14 partially sighted eyes. Results: Flaps with a 6.0 mm diameter and 180 to 200 μm depth were successfully created in most cases. The underlying stroma was treated with a Lambda Physik excimer laser using a 3.5 to 4.5 mm optical zone. Patients were divided into 3 groups for target corrections of 5.0, 10.0, and 15.0 diopters of myopia. Good corneal clarity and refractive undercorrection were recorded in each group 6 months postoperatively. The undercorrection was due in part to the limited optical zone of the laser's delivery system. Some flap decentration was noted. Conclusion: This pilot study indicates that the Nd:YLF picosecond laser may be clinically applied for creating corneal flaps for LASIK. Further refinements of the laser delivery system will include enlargement of the flap diameter and improvements in flap centration. The use of a femtosecond laser may expand the capabilities and precision of this technology.