keratectomy), LASEK (laser epithelial
keratomileusis), and epi-LASIK (epithelial laser in-situ
keratomileusis) use a
laser to reshape the
cornea. By reshaping the cornea, these surgeries
allow light to focus on the
retina and thereby correct a person's
With PRK, the top
layer on the surface of the cornea (epithelium) is removed. Then the laser
reshapes the cornea. The laser removes tissue from the cornea very accurately
without damaging nearby tissues. The layer grows back during the healing
process. PRK may be used to correct
astigmatism at the same time.
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
similar to PRK and LASEK. With epi-LASIK, the surface layer over the cornea is
lifted with a special machine. Like LASEK, the layer is replaced over the
cornea after the laser reshapes the cornea.
PRK, LASEK, and
epi-LASIK are sometimes called surface ablation. They are different from LASIK
(laser in-situ keratomileusis) because they do not involve cutting flaps of the
Many people have PRK or LASEK done instead of
LASIK because of the shape and condition of their eyes. LASEK may also be safer
for people with certain lifestyles, such as professional athletes, police
officers, and firefighters.
LASEK, and epi-LASIK are
outpatient procedures. They are done under
local anesthesia in a surgeon's office or a same-day
surgery center. The procedure takes about 30 minutes, most of which is spent
preparing your eye and the laser. The actual treatment time is very short. Most
treatments take a minute or less (treatment for
farsightedness may take longer than a minute). The
entire process may take about 2 hours, including preparation time, care right
after the surgery, and paperwork.
After surgery, you may wear a
patch or contact lens on the eye and get a prescription for pain medicine.
Someone must drive you home and then back to the surgeon's office the next day.
During this second visit, the surgeon will examine your eye and prescribe
eyedrops to prevent infection and reduce inflammation. More follow-up visits
are required, usually the next week and then throughout the first year after
Unstable vision is common in the first 3 months after
surgery and may last for up to 1 year. The surgery does not always
give 20/20 vision. So you may still need to wear glasses or contact lenses
after the surgery. Your vision may vary slightly over the course of
a day (although not to the point that you would need two pairs of glasses).
LASEK, and epi-LASIK are similar surgeries and are
done for similar reasons. The American Academy of Ophthalmology considers
them safe and effective for mild to moderate
nearsightedness. Most people with nearsightedness fall in this mild-to-moderate
PRK, LASEK, and
epi-LASIK may not be appropriate for people who have more severe
nearsightedness (high myopia), because the results are harder to predict,
complications are more likely, and regression is more likely. Also, PRK may not
be appropriate if you have
In general, for correcting
nearsightedness over 3
diopters, PRK, LASEK, epi-LASIK,
and LASIK are considered more effective than radial keratotomy (RK).
PRK, LASEK, and epi-LASIK are elective,
that correct nearsightedness in otherwise healthy eyes.
The procedure may not be done during pregnancy or breast-feeding. You
also may not be eligible for the surgery if you have an uncontrolled
autoimmune or connective tissue disease.
LASEK, and epi-LASIK work well to reduce mild to moderate
Overall, the results
of these surgeries are stable over the long term. The
results have improved as techniques and lasers have
evolved and changed.
These surgeries tend to have
more stable results than RK, with less need for retreatment and less
hyperopic shift, or increasing
farsightedness, for 8 to 10 years after surgery. For
instance, about 86 out of 100 people have vision within 1
diopter of the intended surgical correction 1 year
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:1
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.3
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 are
The problem most commonly associated
is clouded vision (sometimes also referred to as haze). Some
people's eyes have some clouding of the
cornea as a result of healing. This clouding
may occur about 4 months to 14 months after surgery and
then clear up. It has been linked with spending a lot of
time in the sun.4 Clouding appears to be more common
in people who are very nearsighted. Some doctors may give you eyedrop medicine during and/or after the surgery to lower the chance of
Some doctors may recommend avoiding direct sunlight
for a while after your surgery, taking vitamin C, and wearing sunglasses.
Other complications of these surgeries may
Retreatment may be desired if you have residual
nearsightedness that results from undercorrection or regression.
Serious but rare complications may include:
Experts do not yet
know about all of the long-term side effects or
If you are considering having
surgery to improve nearsightedness, consider all the options (including LASIK, PRK,
LASEK, epi-LASIK, corneal ring implants, intraocular lens
implants, and radial keratotomy), and discuss them with your doctor.
Ask your doctor
the questions that you have about surgery (for example, what are the risks, benefits, and possible outcomes) so that you understand your options and can make the best decision.
PRK, LASEK, epi-LASIK, and LASIK surgery have replaced
radial keratotomy as the refractive surgeries chosen by most people.
Talk with your doctor about the risks and benefits of
correcting both eyes on the same day compared with doing one eye at a
time on separate days.
There is no agreement about whether surface ablation surgeries
are superior to LASIK, or vice versa, for people with mild to
moderate nearsightedness. But with high degrees of nearsightedness, LASIK is
often preferred because of the risk of clouding (haze)
with PRK, LASEK, and epi-LASIK.
The cost of
refractive surgery varies in different locations, but this surgery can be very costly. Most insurance companies do not cover the cost of refractive surgery,
because it is a
Complete the surgery information form (PDF)(What is a PDF document?) to help you prepare for this surgery.
Sakimoto T, et al. (2006). Laser eye surgery for
refractive errors. Lancet, 367(9520):
American Academy of Ophthalmology (2012). Refractive Errors and Refractive Surgery (Preferred Practice Pattern). San Francisco: American Academy of Ophthalmology. Also available online: http://one.aao.org/CE/PracticeGuidelines/PPP_Content.aspx?cid=0bc8c7ce-26df-46da-bf2b-7e908bedaf64.
Katsanevaki VJ, et al. (2007). One-year clinical
results after epi-LASIK for myopia. Ophthalmology,
Kramarevsky N, Hardten DR (2009). Excimer
laser photorefractive keratectomy. In M Yanoff, JS Duker, eds., Ophthalmology, 3rd ed., pp. 131–144. Edinburgh: Mosby
Other Works Consulted
Rajan MS, et al. (2006). Effects of ablation diameter
on long-term refractive stability and corneal transparency after
photorefractive keratectomy. Ophthalmology, 113(10):
June 11, 2013
Kathleen Romito, MD - Family Medicine
& Christopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
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