PRK

PRK (photorefractive keratectomy) was at one time the most common laser eye surgery. It uses the same excimer laser as the LASIK procedure to reshape the outer layer of the cornea to correct for nearsightedness, farsightedness, and astigmatism. Presently LASIK is more common, but PRK is still an excellent alternative for patients who cannot undergo LASIK Surgery.

Reasons to consider PRK:

• Nearsightedness (myopia).
• Farsightedness (hyperopia.
• Astigmatism (irregularly shaped cornea).
• Cornea too thin for LASIK.

The Procedure

In preparation for surgery, anesthetic eye drops are administered. Next, a speculum is placed in the eye to keep the eyelids open, which is normally not uncomfortable. While the patient fixes his or her gaze on a target, the laser reshapes the cornea by removing tissue (a process called ablation), which is controlled and closely monitored by Dr. Chesen. The laser is actually guided by a detailed map of the patient's eye which has been programmed into a computer beforehand. The ablation usually takes less than a minute for each eye, depending on how high the patient's vision prescription is. Most patients feel no pain during the procedure. After the procedure is complete, a contact lens is placed on the eye. The patient may go home shortly after the procedure; however they may not drive themselves.

The Recovery

Dr. Chesen will prescribe pain medication and eyedrops for your recovery . He will also schedule several check-up appointments to monitor the healing process, followed by periodic visits over the next several months. During the recovery process, the patient should rest, and refrain from any strenuous activities for a few days. Most patients can return to work in a day or two.

How PRK Works

The laser used in photorefractive keratectomy is called an excimer laser. It emits a specific wavelength of cold-ultraviolet light energy that vaporizes fractional layers of cells, leaving a very smooth surface.

By carefully sculpting the shape of the outer layer of the cornea, this laser -- a "cool" laser that does not produce heat -- creates an optimal surface layer for the eye's lens.

For nearsighted patients, the laser slightly flattens the top of the cornea. For farsighted people, PRK surgery yields a slightly steeper cornea. In patients with astigmatism, the laser smooths out irregularities.

The equipment Dr. Chesen uses includes a corneal topographer and wavescan instrument that can perform the precise measurements and calculations needed to map your cornea and the desired correction.

PRK is preferred for patients who have thin corneas, as well as patients who have corneal scarring. These conditions would complicate a LASIK procedure and make the patient a less than ideal candidate for LASIK. However, because PRK removes considerably less corneal tissue than LASIK procedures, it is possible to perform this procedure on patients who have issues such as a thin cornea.

Other situations in which PRK is preferred include patients who have job or leisure activities which make them poor candidates for LASIK. This may include patients such as pilots or boxers where there is a high potential for damage to the flap during work or leisure activities. In these cases a procedure which does not require the creation of a flap, such as PRK, eliminates this concern.

Risks of PRK

Any surgery includes risks. PRK is considered safer than LASIK because Dr. Chesen does not cut into the cornea, but works only on the surface.

Many of the risks of PRK are the same as those for LASIK. Night glare is a fairly common side effect and will improve with time. When you reach your 40s, you may still need reading glasses for presbyopia.

Advantages of PRK Eye Surgery

The major advantage of PRK eye surgery is that it is a very uncomplicated procedure and does not require the creation of a flap. Another significant advantage to PRK eye surgery is it is available to many patients who are not ideal candidates for LASIK procedures. Patients who have thin corneas, as well as patients who have work or recreational activities which prevent them from having a procedure involving the cutting of a flap can both benefit from PRK eye surgery.

PRK vs LASIK

The visual outcome is the same. The difference is the first few days after the surgery. In LASIK the cornea is cut and a flap is created. In PRK a very thin layer of cells is removed from the surface of the cornea. The actual laser treatment that is applied to the cornea is the same.

In LASIK the recovery is such that the patient can drive and work the day after surgery. In PRK there are several days of mild to moderate blurry vision. The ability to drive and work varies in these patients.

PRK Healing Time Explained

The PRK healing time is longer than the healing time required for LASIK and improved vision may not be evident for several days. Conversely, LASIK patients may experience improved vision the day after the procedure. The PRK healing process is considered to be slightly more uncomfortable than that of LASIK and may take longer.

Ideal Candidates for PRK Surgery

Dr. Chesen can advise a patient whether or not they are a good candidate for PRK surgery. Patients who are considering this procedure should visit the office for a complimentary screening in order to determine if they are an ideal candidate and if the procedure is likely to be successful. In general, good candidates for PRK surgery include those who have mild to moderate myopia or hyperopia, those who have career or leisure requirements which make having a flap impossible and patients who are not eligible for LASIK based on the shape or thickness of their cornea.

PRK and The Active Career and Lifestyle

Do you have a career that requires a lot of activity such as military, police officer, firefighter, or other types of highly involved action based careers? Do you enjoy a very active lifestyle by doing things such as swimming, skydiving, or scuba diving? Do you have to wear glasses in order to do those things? If so, PRK may be the laser surgery for you!

People with active lifestyles or careers are said to have been recommended to have PRK because you may be more vulnerable to eye injuries. With PRK there is no flap made during the surgery so there would be less of a chance of injury should something come into contact with the eye. Therefore, if you lead an active lifestyle or have a career that is demanding physically, then PRK may be for you.

Frequently Asked Questions

What is PRK?

PRK is the common name for a surgical procedure called photorefractive keratectomy. It uses an excimer laser to sculpt an area on the surface of the eye, rather than making a flap in the cornea, removing an area the thickness of 1 to 3 human hairs and molding the top of the cornea to make accurate and specific corrections to the patient's vision. Nearsighted patients have the cornea flattened while farsighted patients have the cornea steepened.

PRK can be used to treat nearsighted, farsighted, and astigmatic eyes. It has some disadvantages compared to the newer and more common LASIK surgery - notably, a longer recovery time - but is still a valuable option, especially for patients whose corneas are too thin to make them candidates for LASIK. In addition, PRK is one of the procedures most likely to be approved for active-duty members of the U.S. military services.

Who should consider PRK?

PRK is a useful alternative to LASIK for patients who have thin corneas. In addition, some doctors believe PRK to be more effective than LASIK for mild to moderate nearsightedness, though clinical data on this suggest there is not much difference.

Otherwise, the criteria for PRK are the same as those for other forms of refractive surgery. People who have unstable eyes (particularly those uder 18), women who are pregnant or nursing, and those with certain medical conditions are not considered good candidates for successful PRK eye surgery. Dr. Chesen will meet with you to answer any questions you have, but also to test your eyes and take your medical history, before you schedule your surgery.

What to expect before PRK surgery?

During your pre-operative evaluation Dr. Chesen will check for ocular irregularities through a dilation exam, take refractive error measurements, take pupil measurements, take corneal thickness measurements and create a corneal topography map. Additionally, Dr. Chesen will examine your medical history.

You may also have your eyes tested for tear production -- if you have "dry eye" you can still have PRK, but may need to take extra steps to ensure your eyes are hydrated.

You will be asked not to wear your contact lenses for one to three weeks before the procedure in order to allow your cornea to return to its normal shape.

What to expect during PRK?

Your eye will be numbed with anesthetic drops, and you will lie down for the procedure. Dr. Chesen will place a speculum over your eye to hold it open -- this sounds uncomfortable but is not - and you will be asked to look at a target light while Dr. Chesen operates. Try to maintain your focus on this light - it is important to obtain the best results from the surgery. The actual PRK laser eye surgery takes less than a minute. The laser will probably make clicking sounds during the procedure, and you may smell a faint odor. This is normal.

What to expect after PRK surgery?

Dr. Chesen advises taking a few days off from work after PRK surgery. You will also be advised to avoid strenuous exercise for up to a week, as this could get in the way of your healing.

You will wear a special "bandage" contact lens for a few days, and will need to use eye drops for several weeks. You may experience some irritation or discomfort, controllable with over-the-counter medication.

Someone will need to drive you home from your surgery.

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