Lots of patients who are in for a routine eye exam ask about Lasik, but not many have heard of the closely related surgery called PRK. PRK is short for Photo-Refractive Keratectomy and is a technique that uses lasers to reshape the cornea. Much like Lasik, it is an elective surgery that is performed by specialized eye doctors called ophthalmologists to reduce ‘refractive error’ like myopia or astigmatism. To put it another way, these surgeries clear up a patient’s blurry vision, thus reducing or eliminating their need for glasses and contact lenses. Both eyes are typically operated on the same day.
Think of the cornea as a sandwich: there are two pieces of bread and the meat in the middle. In PRK, a laser is used to remove the front layer of the cornea and then reshape the middle layer. After the surgery, the eye is very sensitive, because there is no front layer of the cornea. To help patients heal and deal with the discomfort, a contact lens is placed on the eye. The patient will wear what is known as a ‘Bandage Contact Lens”, which is typically left in place for about a week while the patient grows a new front layer of their corneas. The contact lens helps to control the pain or discomfort but many patients still deal with a bit of eye pain in the early days after surgery. The vision gradually improves as the eyes heal, and most patients end up able to read the 20/20 line, or close to it, without glasses. Most PRK patients take a full week off of work to recover. Some may have persistent dryness or mild to moderate keratitis (irritation and/or dryness of the cornea) after the surgery that can last several weeks, blurring vision during this time, but most do not have this happen. If things are healing more slowly than normal, the treatment is adjusted to get things back on track.
Lasik was invented after PRK in an effort to make the recovery process easier and to reduce discomfort. In Lasik, the front layer of the cornea is loosened with either a precision blade or a laser. This front layer – now called a flap – is moved out of the way. Then a laser reshapes the central layer (stroma) of the cornea, and the flap is put back in place. Typically people have improved but blurry vision right after surgery, and may have significant light sensitivity. After a good night’s sleep, most people wake up the next day and can see quite well. Most patients are able to read the 20/20 line or something close to it without the aid of glasses within 2-4 days. The healing process still requires prescription drops, but no bandage contact lens is typically needed. While no surgery center or co-managing optometrist will promise or guarantee 20/20 vision, the vast majority of patients are pleased with their visual end point.
Most PRK and Lasik patients still have good distance vision even 10 years later, although about one in twenty will have significant regression toward their former glasses prescription. Serious complications of these procedures are rare these days, and are more likely in patients who do not use the prescription drops as directed or otherwise fail to follow their surgeon’s orders (rubbing the eyes, skipping follow up eye exams, etc). Cannon EyeCare refers to both PCLI.com and TLC (The Laser Center) for refractive surgery. For more information on Lasik eye surgery.
Sincerely, Dr. Mark J. Cannon, optometrist @ Cannon EyeCare (at Market Optical) in Seattle, Washington