Radial keratotomy (RK) involves making tiny
cuts in the
cornea, which flatten it and reduce
nearsightedness. In people who have both
astigmatism and nearsightedness, the surgeon may make
additional cuts to flatten the misshapen part of the cornea that is causing the
Because the outcome of surgery on the first eye may
affect how surgery is done on the second eye, many surgeons wait 6 weeks before
treating the second eye. This delay also reduces the risk of spreading a
corneal infection to the second eye. While waiting for the second procedure,
you are usually fitted with a contact lens for the eye that is still
nearsighted, since wearing two very different eyeglass prescriptions causes
What To Expect After Surgery
RK is an outpatient procedure. It is
local anesthesia in a surgeon's office or a same-day
surgery center. The operation on one eye takes about 10 to 15 minutes. The
entire process usually takes less than 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
Recovery is usually quick, with only mild
discomfort. You may return to your normal activities within a few
For 1 to 4 days after
surgery, some people may have pain, aching or throbbing, or a feeling
that there is something in the eye.
Your vision may remain blurry for days to weeks after
surgery. Do not drive until your vision has cleared.
For 2 weeks
after surgery, avoid vigorous sports, eye makeup, and activities that may get
water in the eye. The surgeon may recommend that you shower before the surgery
and then avoid showering for a day or two afterward to keep from getting water
in the eye.
Unstable vision is common in the first 3 months after
surgery and may last for up to 1 year. Your vision may vary slightly over the
course of a day (although not to the point that you would need two pairs of
Why It Is Done
Radial keratotomy is an
elective procedure that is done to correct
nearsightedness in otherwise healthy eyes. Because laser surgeries have become more common than surgeries that involve cutting (incisions), RK is not done very often.
Good candidates for RK have normal, healthy eyes with
stable, mild-to-moderate nearsightedness (up to about 3
diopters) that is not getting worse with time. RK may
also correct some amount of
You may not be eligible for
RK if you have:
Nearsightedness that is still getting worse
(such as in children and teenagers).
changes caused by severe nearsightedness (high myopia), such as retinal
An abnormality or disease of the cornea.
connective tissue disease that might influence the healing of the cornea or
that requires you to take steroids.
A job or hobby for which the
possible side effects of RK would be a problem. Glare is sometimes a side
effect of the surgery, which would be a problem for a truck driver, for
example. People who take part in activities such as contact sports that carry
a high risk of eye or head injury may not be good candidates for RK, because a
blow to the eye in someone who has had RK may cause the
tiny incisions to rupture.
How Well It Works
RK is effective in reducing mild-to-moderate
nearsightedness. It does not always completely
end nearsightedness. You may still need to wear corrective lenses some of
the time for either near or distance vision (or both) after surgery. People who
have moderate-to-high nearsightedness before surgery are more likely to still
need correction for distance vision after surgery than those who are only
The greatest problems with RK surgery are that
the results are harder to predict and they tend to change
over time. RK reduces nearsightedness, but it often causes mild farsightedness
(overcorrection) or does not completely correct
nearsightedness (undercorrection). Results are sometimes several
diopters different than predicted. In contrast,
eyeglasses and contact lenses are fitted with an accuracy of within 0.5 diopter
of the desired correction.
correction after RK also may be unstable. Most people who have RK surgery
gradually become more
farsighted for at least 8 to 10 years after surgery.
This is called the
The most frequent complications of RK include
overcorrection (farsighted after surgery), undercorrection (still nearsighted
after surgery), and unstable vision (hyperopic shift). Retreatment is
sometimes desired to correct these problems.
You may not be able to wear
contact lenses because of the shape of the eye after surgery. Also, RK weakens the cornea, making it more
prone to injury. This is not the
case with other refractive surgeries.
Complications that can occur but are not
A loss in best corrected vision. Before RK,
most eyes can be corrected with glasses or contacts to 20/20 vision or better. A few people who have RK have best corrected vision of
less than 20/20 after surgery. But the vision loss is usually not severe.
astigmatism that causes ghost images or double
Double vision, difficulty seeing how objects are oriented
relative to each other, or loss of fine depth perception.
especially at night. Glare is common in the first 3 months after surgery and
may last longer than 6 months. You may see halos or
radiating lines around headlights or street lamps, and it may be harder for you
to drive at night. Some people have reported that they need to wear sunglasses
or change jobs because of glare.
A few very rare complications may threaten vision,
Experts do not yet know the long-term side effects or
Ask whether the surgeon plans to wait at least 6 weeks before operating on the second eye. With that plan, any unexpected results in the first eye will be less likely to be repeated in the second eye.
What To Think About
If you are considering having
surgery to improve
nearsightedness, consider all the options
(including radial keratotomy, PRK, LASEK, epi-LASIK, LASIK, corneal
ring implants, and intraocular lens implants), and talk about 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 (RK) as the refractive surgeries chosen by most
people. But RK is still very effective for mild nearsightedness (up to 3
diopters) and in other cases.
If you need another type of eye surgery later in
life, such as cataract removal, the corneal scars from RK may make the
operation and recovery more difficult.
The RK surgery is an
elective procedure. The cost of refractive surgery varies
in different locations, but it can be very costly. Most insurance
companies do not cover the cost of refractive surgery.
How this information was developed to help you make better health decisions.