PRK is a procedure that uses a sophisticated, computer-controlled excimer laser which has been specifically programmed for each patient's individual needs, to correct nearsightedness, farsightedness and astigmatism. The laser produces an ultraviolet beam of light that is emitted in pulses. Each pulse delicately removes the microscopic layers of tissue from the cornea (1 /200th of a human hair at a time). The excimer laser is unique in that it emits a "cold" or non-thermal light beam. This makes it ideal for corneal surgery because it eliminates the possibility of thermal damage to surrounding tissue. PRK is the procedure of choice for patients with mild to moderate amounts of myopia and hyperopia. The majority of PRK patients have attained visions of 20/40 or better. In excess of one million people in 40 countries around the world have had PRK. Dr. Rothchild has been involved with the excimer laser for more than 10 years.