During the late 1980's, IBM developed the excimer laser. This laser was initially used to etch computer chips, but researchers felt that the laser had great potential in medicine. Different from most lasers, the excimer laser produces no heat, and thus is called a "cold" laser. The excimer laser simply evaporates cellular material, without affecting surrounding tissue. This allows for precise tissue removal and "shaping" of the cornea.
The initial use of the excimer laser to reshape the cornea was termed PRK, or photorefractive keratectomy. In this procedure, the excimer laser is used to remove a small amount of tissue from the front surface of the cornea, producing a flattening effect and reducing myopia (see section on "myopia"). PRK was rigorously studied by the FDA and was finally approved for use in October of 1995.
PRK differs from LASIK in that there is no corneal flap created and that the laser is delivered directly to the cornea surface. Following PRK, the corneal surface must heal before significant visual improvement occurs. This can take anywhere from a few days, to two weeks. Once the eye heals, results are usually quite good, with as many as 98 percent of patients seeing 20/40 or better after surgery.
Some patients who are not good candidates for LASIK (due to abnormally thin corneas, irregular astigmatism or unusually deep-set eyes) can undergo PRK with great success. PRK has by no means been replaced by LASIK. It is still a useful and viable treatment option.
To find out if you are a good candidate for PRK, please contact us today.