There are two ways to surgically correct refractive vision errors using laser surgery—LASIK and PRK. Both types of laser vision surgeries accomplish the same thing—reshaping the cornea to correct a refractive vision error.
Corneal Shape Causes Refractive Vision Errors
The curvature of the cornea is very influential to your refraction. Laser vision correction works by altering the curvature of the cornea.
A cornea shape that is “steep” focuses light short (in front) of the retina causes myopia (nearsightedness); a cornea shape that is “flat” focuses light past the retina causes hyperopia (farsightedness); and an astigmatism is when the cornea is shaped oblong like a football instead of round like a basketball.
Both PRK and LASIK can correct these with laser surgery.
What is the Difference Between PRK and LASIK?
LASIK requires the creation of a corneal flap before the underlying cornea is reshaped. After the reshaping is completed, the corneal flap is put back in place. Recovery from a LASIK procedure is usually 24-to-48 hours.
PRK does not create a corneal flap prior to reshaping the underlying cornea. The thin layer of cornea that is removed is discarded, but it grows back. However, the recovery time is longer for PRK—about 1 to 2 weeks for initial recovery and about six weeks for sharp vision to be attained.
Both surgeries are performed with high-energy pulses of ultraviolet light from an excimer laser controlled by computer settings programmed to correct your specific refractive error.
The laser penetrates only a microscopic amount of the cornea and can remove as little as 0.25 microns of tissue at a time. For some size comparison—one micron is one-thousandth of a millimeter. A human red blood cell is about 5 microns across. A human hair is about 75 microns across.
Both surgeries are safe and have a high rate of patient satisfaction, but in some cases PRK is the best choice for refractive vision correction.
Factors that can make PRK the Preferred Choice
Corneal Thickness — LASIK requires a thicker cornea than PRK for best results, so if your cornea is extremely thin,PRK might be the right procedure for you.
Refractive Error — If you have a high degree of myopia, -8.00 or -9.00 diopters, then PRK is often the right procedure for you and that’s because there may not be enough residual corneal tissue for the LASIK flap.
Career — If you work in an industry such as construction, law enforcement, or the military where eye trauma is more likely than in other occupations, PRK might be the right choice for you because the flap created in LASIK could cause complications in the event of a work-related eye trauma.
Hobbies — If you participate in contact sports, martial arts, or other types of high-intensity competition, your eyes are exposed to potential trauma during those activities and so, again, PRK may be the best choice for you.
Consult Your Doctor
During your consultation, we will help you determine whether your cornea thickness, refractive error, or your career or hobbies make PRK the best choice for you.