Photorefractive keratectomy (PRK) is a form of refractive eye surgery which aims to reduce the need for correction with glasses or contacts. PRK uses a specific type of laser (called an excimer laser) to reshape the cornea and correct near sightedness, far sightedness and/or astigmatism. During PRK the outer layer of the cornea, called the epithelium, is removed and a laser called an excimer laser is used to remove a portion of the cornea. The epithelium is then allowed to heal and regrow which usually takes 3-7 days. The vision will initially be blurry and gradually improve as the epithelium regrows. Often, a bandage contact lens is placed on the eye to aid in healing and to help reduce discomfort after the procedure.
The amount and location of the cornea removed is determined by preoperative measurements. Removal of this section of the cornea changes the corneal curvature and the overall refractive power of the eye with an overall goal of reducing the patient's need for glasses. PRK is typically performed in an outpatient surgery center or medical office with a special room for performing refractive surgery.
After surgery you will need to use eye drops to help prevent infection and reduce inflammation. It is also typical to need lubricant eye drops or artificial tears. During the postoperative period there will be restrictions on certain activities including but not limited to touching/rubbing the eyes, wearing makeup, and/or swimming. Specific instructions will be given to by the surgeon at the time of surgery and these should be followed to ensure proper healing.
Who Is A Good Candidate For PRK?
Only an ophthalmologist is trained to know if you are a good candidate for PRK, so you will need to schedule an evaluation with a refractive surgery specialist. Refraining from contact lens use for a specific period of time prior to the evaluation will be required to ensure accurate measurements, this period is usually two weeks. A complete eye exam including refraction, corneal topography, dilated exam and corneal thickness measurement will determine if a patient is eligible for PRK. Criteria which make a patient a good candidate for PRK include myopia in range of -1 diopter to -10 diopters, hyperopia in the range of +1 diopter to +6 diopters and/or astigmatism in the range of 1 diopter tp 5 diopters, generally healthy eyes, age 22 or older with a stable refraction. There are certain medical conditions or eye characteristics which will make a patient a poor candidate for PRK. These include thin corneas, visually significant cataracts, advanced glaucoma, uncontrolled diabetes, excessive scarring or keloid formation, or women who are pregnant or nursing.
LASIK VS. PRK
Unlike LASIK, PRK does not involve creating a flap prior to lasering the corneal bed. This allows PRK to be an option for some patients that are not good candidates for LASIK due to thin corneas. However, there are still criteria which must be met regarding refractive error and corneal thickness to ensure PRK can be done safely. There is also evidence that PRK can result in fewer damage to corneal nerves resulting in fewer dry eye symptoms. Due to there being no fap creation, PRK does not pose a risk for a dislodged flap from eye trauma after surgery. PRK is an elective procedure to reduce the need for glasses and contacts. For this reason, it is typically not covered by vision or medical insurance. The cost of PRK varies but is often in the range of $1,000-$3,000 per eye.
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