Photorefractive Keratectomy (PRK)

PRK, photorefractive keratectomy, treats nearsightedness (myopia) farsightedness (hyperopia) and astigmatism by removing a microscopic amount of tissue from the front surface of the cornea with an excimer laser (see refractive surgery section for details). By changing the shape of the cornea, light is focussed clearly on the retina in the back of the eye.

PRK may be performed on one eye at a time or on both eyes at the same session. First, the eye is anesthetized with drops. During the laser procedure, the patient stares at a blinking colored light. Next, with the cornea properly exposed, computer-controlled pulses of excimer laser light (yellow arrows) are directed onto the cornea (blue dome) to delicately reshape the curvature of the eye. The laser removes the proper amount of tissue (red area), a layer about as slender as a human hair, within less than a minute. As shown in b, the corneal surface has been slightly flattened, correcting myopia.

After PRK, antibiotic drops and anti-inflammatory drops along with a soft contact lens will be placed into your eye to improve comfort and to protect your eye during healing. Once the surface of the cornea is healed, usually on the second postoperative day, the soft contact lens is removed. You will be examined on the first and second day following surgery to ensure that there are no problems.

You will be treated with a mild steroid (anti-inflammatory) drop for 2-3 months following the procedure, during which time you will be examined every month. Final visual results are usually realized anywhere from several days to a few months.



Comparison of PRK & LASIK

	PRK	LASIK
Range of Correction	Low to moderate	Low to severe
Wound Depth	Superficial	20% deep
Intraoperative Pain	None	None
Post-operative Discomfort	Minimal, 12-24 hours	Minimal, 12 hours
Post-operative Medications	2 to 4 months	4 days
Functional Vision Recovery	3 to 5 days	24 hours
Return to Work	1–2 days	1 day
Risk of Complications	Low (less surgeon dependent)	Low (more surgeon dependent)
Risk of Corneal Scarring	1 ~ 2 %	<1 %
Patient Satisfaction	High	Very High