Until recently, if you were one of the millions of people with a refractive error, eyeglasses and contact lenses were the only options for correcting vision. But with the arrival of refractive surgery, some people with myopia (nearsightedness), hyperopia (farsightedness), or astigmatism (a cornea with unequal curves), may have their vision improved through surgery.
Laser assisted in situ keratomileusis, or LASIK, is a refractive procedure that uses an automated blade and a laser to permanently reshape the cornea. The reshaped cornea helps focus light directly onto the retina to produce clearer vision.
LASIK is usually performed as an outpatient procedure using topical anesthesia with drops. The procedure itself generally takes about fifteen minutes. The surgeon creates a flap in the cornea with a microkeratome. The flap is lifted to the side and the cool beam of the excimer laser is used to remove a layer of corneal tissue. The flap is folded back to its normal position and sealed without sutures. The removal of corneal tissue permanently reshapes the cornea.
A shield protects the flap for the first day and night. Vision should be clear by the next day. Healing after surgery is often less painful than with other methods of refractive surgery since the laser removes tissue from the inside of the cornea and not the surface. If needed, eye drops can be taken for pain and usually are only needed up to one week.
Some people experience poor night vision after LASIK. The surgery may result in under correction or overcorrection, which can often be improved with a second surgery. More rare and serious complications include a dislocated flap, epithelial ingrowth and inflammation underneath the flap. Most complications can be managed without any loss of vision. Permanent vision loss is very rare.
The ideal candidate for LASIK has a stable refractive error within the correctable range, is free of eye disease, is at least 22 years old and is willing to accept the potential risks, complications and side effects of LASIK.
Photorefractive Keratectomy (PRK)
Photorefractive Keratectomy (PRK) is another technique that uses a laser to sculpt the surface of the cornea to treat refractive error. The procedure is effective in treating low to moderate levels of myopia or hyperopia with or without astigmatism. During the PRK procedure, the outer layer of the cornea, called the epithelium, is removed. There is no creation of a partial thickness flap with a microkeratome as is done in LASIK. A cool laser beam is applied to the cornea and a soft contact lens is applied to serve as a bandage during the healing process.
This contact lens will be removed within five to seven days of the procedure. Recovery is usually two to three weeks, during which the patient may have mild to marked discomfort and blurry vision. Most of the vision improvement is seen in the first month, but there is still gradual improvement over the year after the initial procedure. Results take longer to achieve with PRK than LASIK because it takes longer for the epithelium to be restored.