PRK, or Photorefractive Keratectomy, differs from LASIK in that it does not involve the creation of a corneal flap. The Excimer laser beam is applied directly to the surface of the cornea. By eliminating the flap creation step, the risk of flap complications is eliminated allowing for a very safe, very precise correction.
In preparation for surgery, your eye will be numbed with anesthetic eye drops. Once your eye is numb, our surgeon will place an eyelid holder between your eyelids to prevent blinking during the procedure. The surgeon will then delicately remove the epithelium, a thin layer of skin that makes up the protective outer layer of the cornea. At this point, a precise, computer-controlled laser beam will be applied to reshape the exposed cornea, according to specific calculations taken in your pre-operative exam. Within seconds, millions of laser pulses will reshape your cornea to correct the specific refractive error. After completion of the surgery, a bandage contact lens will be placed on your eye for improved comfort. Because there is no protective flap created as in the LASIK procedure, it usually takes three to five days for the outer epithelium layer to re-grow over the cornea. During that period, you may experience mild discomfort and sensitivity.
During your pre-operative consultation at Vance Thompson Vision, our doctors will recommend that you consider either a conventional PRK correction or a custom PRK correction. The difference between the two procedures involves the amount of unique visual irregularities that are present in your cornea and lens.
Custom PRK corrects those irregularities that cannot be addressed by glasses, contact lenses or conventional laser surgery. These distortions, called “aberrations,” are classified as lower order aberrations or higher order aberrations. Lower order aberrations including nearsightedness, farsightedness and astigmatism are responsible for approximately 90% of your visual blur. Higher order aberrations account for the remaining blur and affect the clarity of your vision, especially in lowlight situations. Custom PRK technology uses highly sophisticated instrumentation to generate a structural map of both your lower and higher order aberrations. Then, our laser radar tracking device tracks the eye to guide the laser to precisely reshape your cornea. The goal of Custom PRK is to give you better results than conventional PRK correction.