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PRK - Photorefractive Keratectomy
Photorefractive keratectomy, or PRK, is a type of laser eye surgery used to correct mild to moderate nearsightedness, farsightedness, and/or astigmatism.
All laser vision correction surgeries work by reshaping the cornea, or clear front part of the eye, so that light traveling through it is properly focused onto the retina located in the back of the eye. There are a number of different surgical techniques used to reshape the cornea. During PRK, an eye surgeon uses a laser to reshape the cornea. This laser, which delivers a cool pulsing beam of ultraviolet light, is used on the surface of the cornea, not underneath the cornea, as in LASIK.
What Are the Advantages of PRK Eye Surgery?
PRK eye surgery is highly accurate in correcting many cases of nearsightedness. Approximately 80% to 90% of PRK patients have 20/20 vision without glasses or contact lenses one year after the surgery; 95% to 98% have 20/40 or better without glasses or contacts.
PRK (photorefractive keratectomy) is a type of refractive surgery to correct myopia (nearsightedness), hyperopia (farsightedness) and astigmatism.
PRK was the first type of laser eye surgery for vision correction and is the predecessor to the popular LASIK procedure. Though PRK recovery takes a bit longer than recovery from LASIK eye surgery, PRK is still commonly performed and offers advantages over LASIK for some patients.
The main difference between PRK and LASIK is that in LASIK surgery a thin, hinged flap is created on the cornea to access the treatment area, whereas in PRK the cornea's entire epithelial (outer) layer is removed to expose the area and no flap is created. For both PRK and LASIK, the excimer laser then sculpts the stromal layer of the cornea to correct your refractive error.
The final results of PRK surgery are comparable to LASIK outcomes, but initial PRK recovery is slower because it takes a few days for new epithelial cells to regenerate and cover the surface of the eye.
PRK does, however, offer some distinct benefits. Because PRK surgery does not create a corneal flap (which contains both epithelial and the deeper stromal tissues), the entire thickness of the underlying stroma is available for treatment. This is of particular benefit if the cornea is too thin for LASIK or if you have undergone LASIK previously and therefore have a thinner residual cornea. There also is no risk of flap complications, and the risk of removing too much of the cornea with the excimer laser is reduced.
How Is PRK Performed?
First, your eye surgeon removes a central area of corneal epithelium with an alcohol solution, a "buffing" device or a blunt surgical instrument. Next, an excimer laser is used to precisely reshape the curvature of your cornea's surface. This computer-controlled, highly specialized laser delivers pulses of cool ultraviolet light that remove microscopic amounts of tissue in a precise pattern. A soft contact lens "bandage" is then placed on the cornea to help protect your eye. New epithelial cells grow back in five days typically, after which the bandage contact lens is removed by your eye doctor.