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Gastroenterology
Photo-Refractive Keratectomy (PRK)



Photo-Refractive Keratectomy (PRK)

Before the Procedure

Before your doctor can decide if you are a candidate for this procedure, he will have to evaluate your condition during a consultation visit. He will perform a medical history and physical and complete eye exam. He will discuss with you the therapeutic choices available to you and determine if you are a good candidate for PRK. If so, an appointment will be made at the local outpatient surgical facility. For most patients undergoing the PRK procedure, there is no need for hospitalization. In fact, the procedure only takes about 20 minutes to complete, about the same length of time as LASIK. Most patients are amazed how simple and painless the process is. A mild sedative is sometimes administered to relax the patient and relieve any anxiety. Before the procedure, the doctor applies anesthetic eyedrops to numb the eye. An eyelid support is inserted to prevent blinking while the drops eliminate the natural reflex to blink.

Removing the Epithelium

The cornea is composed of 5 layers, from the front to the back:

1. epithelium
2. Bowman's membrane
3. stroma
4. Descemet's membrane
5. endothelium

Epithelium is the type of tissue that covers all free body surfaces. In the PRK procedure, the top protective epitheial layer of the cornea is first removed revealing the next layer known as Bowman's membrane. This removal can be performed mechanically or with the laser. This layer regenerates itself every few days. Since the surgeon typically only removes a layer about as thick as a human hair, the cornea maintains is original strength.

Reshaping the Surface

Excimer Laser

Once the epithelium has been removed, the surgeon then uses the VISX STAR Excimer Laser System to apply computer controlled pulses to the cornea's surface to reshape its curvature based on the predermined exact vision prescription. Each laser pulse showers down 25 billon photons (packets of light engergy) onto the central portion of the cornea, removing .25 microns of tissue with each pulse. (One micron equals one one-thousandth of a millimeter.) This delicate reshaping then allows light rays to focus properly on the retina. The Eximer laser is so precise, it can notch out a human hair. The laser does its work in about a minute. The entire process is painless and takes about 20 minutes.

Upon completion of the laser aspect of the treatment, te area is then irrigated and inspected carefully. Antibiotic eye drops are administered and an eyepatch is applied.

Recovery

The patient returns to the recovery room for a short rest, given postop instructions, and then is allowed to return home to the care of a companion. Post-operatively, PRK patients are fitted with a protective contact lens to improve the comfort during healing while the surface protective layer is healing. Rubbing the eye should be avoided for the first few weeks while the epithelium continues to heal. PRK patients report some discomfort after the procedure until the cornea's outer surface heals, usually within 2 tp 3 daus. Some patients report dramatic improvement in their vision within the first week while other experience some visual fluctuations for several weeks to months. Most patients return to normal activities within one to three days. After the first week, PRK patients can generally resume their full exercise activities while protecting the eye against injury or accident.

PRK patients are placed on antibiotic drops and anti-inflammatory drops to promote rapid safe healing and ensure comfort. Once the epithelial protective layer is healed, usually on the third post-operative day, the bandage contact lens is removed. PRK patients are then maintained on steroid anti-inflammatory drops for 1 to 4 months. Patients are able to fly immediately after either PRK or LASIK and cautiously resume exercise and swimming after 1 week.

Benefits of PRK

The following are some of the benefits of PRK:

  • less invasive
  • low infection risk
  • relatively quick procedure to complete
  • high degree of predictability
  • excellent ocular integrity post-treatment

Possible risks of PRK

Side effects are minimal following PRK surgery, but people who have the surgery may experience some light sensitivity and glare for a few days or weeks. Full visual stabilization may take several weeks. Possible rare complications may include:

  • Irregular healing of cornal surface and some visual distortion
  • Infection - Very rare and usually controlled with medications.

Copyright:

Daniel J. Nadler, M.D.

Daniel J. Nadler & Associates
Eye Physicians and Surgeons

Sewickley Office
409 Broad Street - Suite 270
Sewickley, PA 15143
Phone 412 741-5577
Beaver Office
1200 Sharon Road - Suite 202
Beaver, PA 15009
Phone 724 774-5920


Text & Images Courtesy of Three Rivers Endoscopy Center
© Dr. Robert Fusco, Three Rivers Endoscopy Center, All Rights Reserved





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