LASIK eye surgery is surely the best known of the laser treatments to correct common focal problems. However, LASIK is not the only such treatment. Two other popular treatments are PRK (Photorefractive keratectomy) and LASEK (Laser-Assisted Sub-Epithelial Keratectomy or LASer Epithelial Keratomileusis). In this article we will compare PRK and LASIK.
LASIK surgery involves cutting a flap of tissue in the cornea approximately 100 to 180 microns or micrometers thick (.001 mm!). The laser is then used to reshape the cornea to correct the problems of nearsightedness, farsightedness, or astigmatism. The procedure is relatively pain-free because the sculpting is done below the nerve endings in the cornea. Full healing is expected in one to three months. Stitches are not required because the flap is kept in place by the natural pressure of the eyes.
This flap, however, is the main disadvantage of LASIK surgery. This is because it can affect the correction and can cause hazy vision. The flap can also be dislocated, thus causing the need for further repair. This happens in about 1% of the patients. It has also been a problem in the past that LASIK misses the exact center of vision, causing double vision. Because the sculpting is done within the cornea, healing is quicker.
PRK, on the other hand, similarly involves sculpting the cornea but on the outside. Thus no flap is cut into the cornea. Instead the outer layer of the cornea, called the epithelial layer, is removed. A contact lens is placed on the eye for two to five days after surgery to protect the cornea as it begins to regenerate. Because no flap was cut into the cornea, the problems mentioned above are eliminated. However, with PRK there will probably be more pain since most of the pain receptors are on the surface of the cornea. Also, expect a longer time to recover from PRK. Full healing usually occurs in three to four months.
Most nearsighted people qualify for PRK laser surgery, but not all. Some criteria include age 18 or more, stable refraction error (eyes aren’t changing), free of diseases such as glaucoma, vascular disease, diabetes and rheumatoid arthritis, and freedom from other eye diseases.
PRK is not without risk either. The most common complication is dry eyes. This is the most common complication for all laser eye surgeries. Others include glare, halos, wrong correction, reduced ability to see in low light, or chromic pain. About one to three percent of patients have worse vision following surgery than they had before.
To know if PRK or LASIK refractory corrective surgery is right for you, consult an optometrist or ophthalmologist who is trained in these procedures. Risk is a factor in all surgeries, but now after more than ten years, the risk if small.