Photorefractive Keratectomy (PRK)

Photorefractive keratectomy, commonly referred to as PRK, is a type of refractive surgery used to correct vision problems such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. This procedure involves the use of an excimer laser to reshape the cornea, which is the clear dome-shaped surface at the front of the eye.

Procedure Overview

The PRK procedure typically begins with the administration of numbing drops or a local anesthetic to minimize discomfort during the surgery. The surgeon then removes the outer layer of the cornea, known as the epithelium, either manually or with the help of a specialized instrument. Following this, an excimer laser is used to reshape the underlying corneal tissue according to the patient's specific refractive error.

How PRK Works

The excimer laser emits high-energy pulses that remove microscopic amounts of tissue from the cornea with each pulse. The pattern of removal is programmed into the computer controlling the laser, based on the measurements of the patient's eye taken before surgery. By reshaping the cornea, the focal point of light entering the eye is adjusted to properly focus on the retina, thereby correcting vision.

Recovery and Aftercare

After PRK, patients typically experience some discomfort, including pain, blurred vision, and sensitivity to light. The epithelium takes a few days to heal, during which time the patient may need to use bandage contact lenses to protect the eye and promote healing. Medications are prescribed to manage pain and prevent infection. Vision may be blurry for several weeks as the cornea heals, but most patients can return to their normal activities within a week or two.

Advantages

PRK has several advantages over other types of refractive surgery, such as LASIK. One key benefit is that it does not involve creating a flap in the cornea, which reduces the risk of certain complications like dry eye syndrome and flap-related issues. Additionally, PRK can be suitable for patients with thinner corneas who may not be good candidates for LASIK.

Risks and Complications

While generally safe, PRK carries risks and potential complications, including infection, undercorrection or overcorrection of the refractive error, dry eye, and haze. Haze is a condition characterized by the formation of scar tissue on the cornea, which can affect vision clarity. In most cases, these complications are temporary and resolve with time or additional treatment.

Outcomes

The outcomes of PRK vary among individuals but generally result in significant improvement in uncorrected vision (vision without glasses or contacts). The success rate for achieving 20/40 vision or better is high, although some patients may still require corrective lenses for optimal vision. Long-term results are typically stable, with the cornea maintaining its new shape.