PRK, LASEK, and epi-LASIK work well to reduce mild to moderate nearsightedness.^{footnote 1}

Overall, the results of these surgeries are stable over the long term. The results have improved as techniques and lasers have evolved and changed.

Almost everyone notices improvements in their vision after one of these surgeries. But not everyone gets perfect 20/20 vision. Studies show that after PRK or LASEK:^{footnote 1}

• More than 94 out of 100 people have 20/40 vision or better.
• More than 61 out of 100 people who had PRK and more than 74 out of 100 people who had LASEK have 20/20 vision or better.

In a study done one year after epi-LASIK treatment, all of the people's eyes had 20/40 vision or better. And more than 3 out of 4 eyes had 20/20 vision or better.^{footnote 2}

In general, most people with mild or moderate nearsightedness can expect to have uncorrected vision of 20/40 or better (without glasses or contacts) after surgery. Results in people who are more nearsighted are harder to predict.

The risks associated with PRK, LASEK, and epi-LASIK for nearsightedness and farsightedness are similar.

One of the most common problems is clouded vision (sometimes also called haze). Some people's eyes have some clouding of the cornea as a result of healing. This clouding may occur within a year after surgery and then clear up. It has been linked with spending a lot of time in the sun. Clouding appears to be more common in people who are very nearsighted. Some doctors may give you eyedrop medicine during or after the surgery to lower the chance of haze.

Avoid direct sunlight and wear sunglasses for as long as your doctor recommends. The doctor may also advise you to take vitamin C.

Other complications of these surgeries may include:

• Dry eyes. For a few months after your surgery, you may need to use artificial tears without preservatives.
• Night vision problems, such as halos. (These are often described as a shimmering circle around light sources such as headlights or street lamps.)
• Glare, or being more sensitive to bright light.
• Double vision (diplopia), usually in one eye. Some people describe this as "ghosting" around an object, rather than a doubling.
• New astigmatism.
• Overcorrection, undercorrection, or regression. These are caused by abnormal healing of the cornea or thickening of the treated area. Some doctors suggest medicines to limit it.
• Loss of best corrected vision, which is the best possible vision you can achieve using glasses or contact lenses. This loss isn't common. But the risk rises with severe nearsightedness.

You may get treatment again if you end up with nearsightedness caused by undercorrection or regression.

Serious but rare complications may include:

• Infection.
• Sores (ulcers) on the cornea.
• Elevated pressure inside the eye (intraocular pressure) and glaucoma.

Experts don't yet know about all of the long-term side effects or complications.