PRK (Photo Refractive Keratectomy)
Imagine being able to work, drive, read the clock, play sports, ride horseback-do just about everything-without always having to reach for your glasses or contacts. An eye treatment called PRK (photo refractive keratectomy) could make this a reality for you. If you’re a candidate for PRK, your eye doctor can reshape the surface of your eye using a laser, so that images focus more clearly. The result can be a dramatic improvement in your distance vision-and your lifestyle.
Could PRK Change Your Life?
Being dependent on glasses and contacts can cramp your lifestyle. Glasses fog up, fall off, scratch, and break. Frames and thick lenses interfere with side vision. Contacts can irritate your eyes, especially if dust gets under a lens or you have dry eyes or allergies. Both glasses and contacts can limit your choice of careers or sports. PRK could reduce or eliminate your need for glasses and contacts-without weakening your eyes.
Patients are referred to Virginia Eye Consultants through our network of highly qualified Doctors of Optometry. At VEC, we take great pride in our relationships with our optometric referral network. We believe in the co-management model which shares the responsibility of patient care between VEC specialists and our OD network.
Learn More about our Optometric Partnerships
Is PRK for You?
The success of PRK depends mainly on your eyes. You may be a good candidate for PRK if your vision is stable, you have low to moderate myopia (nearsightedness) and you have no other eye problems. You also need to understand the possible risks and be realistic about what to expect.
PRK works well for most people, but there is no guarantee that you’ll have perfect vision or never need distance or reading glasses again. PRK does not change your vision overnight. It takes several weeks to months for your eye to heal and your vision to clear completely. The procedure is painless, but you can expect to have some discomfort for a few days afterward.
Evaluating Your Eyes
Your eye doctor will examine your eyes to make sure PRK is right for you. Your eyes will be dilated and your refraction (the way light focuses in your eye) measured. Your doctor will also examine your cornea (the clear covering of your eye), take computerized measurements (corneal topography) of the shape of the cornea, and measure the thickness of the cornea using ultrasound. These and other tests help your eye doctor detect any problems that could make PRK the wrong decision for you.
Possible Risks of PRK
Before PRK, you’ll be asked to sign a consent form. Your eye doctor will discuss with you the risks and possible complications following PRK. A haze may develop in the cornea during the first few weeks after surgery. Normally, this clears quickly. If it does not, vision can be cloudy for months. Only rarely is the haze permanent. There is a very small risk of infection, which could scar the cornea and decrease vision. Vision could worsen or astigmatism (irregular curvature of the cornea) or farsightedness develops. Variable vision is also possible, but unlikely. The pressure inside the eye may temporarily rise as a result of the eye drops used after surgery. With some lasers , complaints of glare and halos are commonly reported following PRK. However, given the larger ablation zones of the Alcon Wavelight system this is rarely troublesome A second treatment could be needed if nearsightedness is not sufficiently corrected.
Correcting your Vision with PRK
How clearly you see depends in part on the shape of your cornea. During PRK, your eye doctor uses an excimer laser to reshape the surface of the cornea. This allows light to focus more clearly in your eye and brings your vision closer to normal. Because a computer calculates the amount of tissue to be removed, the procedure is extremely precise. Not all eyes heal at the same rate, so usually only one eye is corrected at a time. This allows you and your doctor to evaluate the results before treating the second eye.
The Normal Eye
In the normal eye, the cornea is a rounded curve. Light rays pass through the cornea and the pupil through the lens, which refracts, or focuses, the light onto the retina (alight-sensitive tissue inside the eye). The resulting image is clear.
The Myopic Eye
In the myopic eye, the cornea is too steeply curved for the length of the eye (the distance from the cornea to the retina). As a result, light rays focus in front of the retina, and images look blurred or fuzzy. The farther away an object is, the more out of focus it will appear.
What is an Excimer Laser?
An excimer laser is a concentrated beam of ultraviolet light that can be precisely focused. The beam is so accurate that it can cut notches in a human hair. And because the excimer laser doesn’t generate heat, the surrounding tissue is rarely damaged.
Your Excimer Experience
You’re awake during treatment, but your eye is numbed with drops so you feel no pain. You lie flat in a reclining chair so that your eye is aligned with the laser beam. Your eyelid is held open with a special instrument. Your doctor first removes the top (epithelia) layer of your cornea. Then you look at a light to keep the laser beam centered over your eye. You’ll hear a sound as the laser reshapes the surface of your cornea. The Wavelight laser typically takes less than 15 seconds. You’ll probably be in and out of the doctor’s office or surgery center in about an hour.
How the Laser Reshapes Your Eye
To correct myopia, your eye doctor uses the excimer laser to reshape the curve of the cornea. Your refraction is entered into a computer, which calculates the depth and the pattern of tissue to be removed. The laser then delivers a programmed number of overlapping pulses of ultraviolet light. Each pulse removes a microscopic layer of the cornea over the pupil. More pulses are directed at the center of the cornea to flatten the curve. Overlapping the pulses creates a smooth surface. When the center of the cornea is flattened, light rays are focused more directly on the retina and images are clearer.
Your Recovery and Follow-Up
After treatment, your eye needs time to heal. Your vision will be blurry at first, but it should start to clear in 3-4 days. Your doctor will monitor your recovery over the next few months. You can probably expect maximum improvement in your vision within 2-3 months after PRK.
As Your Eye Heals
To protect the cornea as it heals, a soft contact lens or patch is placed on the eye. Your doctor will also give you one or more types of eye drops to help control pain, prevent infection, and promote healing. Your vision will clear as your cornea heals. You can help by using your eye drops as directed and by following a few do’s and don’ts.