Excimer laser photorefractive keratectomy (H-PRK) and laser epithelial keratomileusis (H-LASEK) for farsightedness

Surgery Overview

Photorefractive keratectomy (H-PRK) and laser epithelial keratomileusis (H-LASEK) for hyperopia are newer and more difficult procedures than PRK and LASEK for nearsightedness (myopia). H-PRK and H-LASEK procedures use a laser to reshape the cornea so that light is refocused on the retina. The laser reshapes the cornea accurately without damaging nearby tissues.

Either procedure may be used to correct farsightedness and astigmatism at the same time.

These procedures can be performed on an outpatient basis in a surgeon's office or same-day surgery center. With H-PRK, surface skin cells of the cornea are removed, and a laser is used to reshape the cornea. Unlike LASIK, no flap is cut. The H-PRK procedure is similar to PRK for myopia, but the laser portion takes a little longer, an average of about a minute or a minute and a half. The whole procedure, including preparation and surgery, takes about 20 minutes.

With LASEK, the surface layer of the cornea is loosened and pushed to the side. After the laser reshapes the cornea, the surface layer is placed back over the cornea.

H-PRK and H-LASEK are sometimes called surface ablation. They are different from LASIK (laser in-situ keratomileusis) because they do not involve cutting flaps of the cornea.

What To Expect After Surgery

You will wear an eye shield, a bandage, or special contact lens for 2 to 3 days after surgery, and your doctor will prescribe eyedrops to reduce inflammation and the risk of infection. You may need to use eyedrops for several months after surgery. Several follow-up visits are needed.

Recovery from H-PRK is longer and more painful than recovery from H-LASIK. The eye can be quite painful for 2 to 3 days. Your vision will be reduced for several days after surgery, until the surface skin cells heal. Recovering from H-LASEK surgery may not be as painful as the with H-PRK procedure.

Why It Is Done

H-PRK and H-LASEK are similar surgeries and are performed for similar reasons.

The American Academy of Ophthalmology considers both surgeries safe and effective for mild to moderate farsightedness. Specifically, H-PRK has been approved for use in the United States in people age 21 and older who have farsightedness of 1.0 to 6.0 diopters.¹

H-PRK or H-LASEK may not be appropriate for people who have more severe farsightedness (high hyperopia), because the results are harder to predict and complications are more likely.

Both are elective, cosmetic procedures, done to correct farsightedness in otherwise healthy eyes.

These procedures may not be done during pregnancy, because pregnancy may interfere with the healing of the cornea.

How Well It Works

H-PRK and LASEK effectively reduce mild to moderate farsightedness.

Photorefractive keratectomy for hyperopia was approved in the U.S. in 1998. H-LASEK has not yet been approved but is considered appropriate for off-label use. Little is known about long-termor effectiveness of either procedure.

In the short term, H-PRK has proven effective in correcting mild to moderate hyperopia. One clinical trial showed that one year after surgery, 92% of people who had the procedure had 20/40 vision or better, and 95% were within 1.0 diopter of the intended correction.²

Risks

One problem commonly associated with H-PRK is clouded vision (sometimes referred to as haze). Most eyes treated with H-PRK have some clouding of the cornea as a result of healing.

Other complications of H-PRK may include:

• Night vision problems, such as halos (often described as a shimmering circular zone around light sources such as headlights or streetlights).
• Glare, or increased sensitivity to bright light.
• Double vision (diplopia), usually in one eye.
• New astigmatism.
• Regression. As the cornea heals, cells may fill in the area that was reshaped by the laser, causing at least some of the farsightedness to come back. Regression may also occur if the treated area thickens as part of the healing process. Regression may occur up to 2 years after surgery. Medications are sometimes used to control and limit regression.
• Slow recovery of best corrected vision.

Serious but rare complications may include:

• Infection.
• Elevated pressure inside the eye (intraocular pressure) and glaucoma.

H-PRK is considered safe. No deaths have been reported as a result of the operation, and serious complications are rare. But H-PRK is a relatively new procedure, and it may have long-term side effects or complications that are not yet known.

H-LASEK has similar risks to H-PRK. In addition, there is a risk of the epithelial flap coming loose after surgery and causing pain.

What To Think About

If you are considering having surgery to improve farsightedness, consider the different options (H-LASIK, H-PRK, H-LASEK, LTK, CK, and intraocular lens implants) and discuss them with your doctor.

Although H-PRK and H-LASEK are viable options in the correction of farsightedness, H-LASIK is the preferred procedure because of its quicker healing time and quicker visual recovery.

Both H-PRK and H-LASEK are cosmetic procedures. The cost of refractive surgery varies in different locations, but it can be a significant expense. Many insurance companies do not cover the cost of refractive surgery.

Complete the surgery information form (PDF)(What is a PDF document?) to help you prepare for this surgery.

Author:	Jeannette Curtis	Last Updated: November 23, 2007
Medical Review:	Kathleen Romito, MD - Family Medicine Christopher J. Rudnisky, MD, FRCSC - Ophthalmology
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