Radial keratotomy (RK) is a surgery to correct nearsightedness. It involves making tiny cuts in the cornea to flatten it. This can help improve distance vision. The surgeon may make more cuts to the cornea if you also have astigmatism.
RK is done in a surgeon's office or a same-day surgery centre. Before surgery, your eye will be numbed with eyedrops (local anesthesia).
How well surgery works on the first eye may affect how surgery is done on the second eye. That's why many surgeons wait up to 6 weeks before treating the second eye. This delay also reduces the risk of spreading an infection to the second eye. While you wait for the second surgery, you will probably be fitted with a contact lens for the untreated eye. Wearing glasses with two very different prescriptions would cause distorted vision.
What To Expect After Surgery
Surgery on one eye takes about 10 to 15 minutes. You will need someone to drive you home. You will also need a ride to the surgeon's office the next day.
The surgeon will check your eye the day after surgery. You will have more follow-up visits throughout the first year after surgery.
After surgery, you may wear a patch or contact lens on the eye. You may get a prescription for pain medicine and for eyedrops to prevent infection and reduce swelling.
- Recovery is usually quick. You may return to most of your normal activities within a few days.
- Most people have only mild discomfort. But some people may have pain, aching, throbbing, or a feeling that there is something in the eye for 1 to 4 days after surgery.
- Your vision may be 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. Your doctor will tell you when you can shower.
In the first 3 months after surgery, your vision may vary slightly over the course of a day. This may last for up to 1 year.
Why It Is Done
RK is done to correct nearsightedness. It may also reduce astigmatism. But RK is not done very often. Laser surgeries have become more common than surgeries that involve cutting.
RK may be an option if you have healthy eyes with mild-to-moderate nearsightedness (up to about 3 dioptres) that is not getting worse with time.
RK may not be an option if you have:
- Nearsightedness that is still getting worse. This is often the case with children and teenagers.
- Pathological myopia, which causes rapid changes in vision.
- Changes caused by severe nearsightedness (high myopia) that get worse over time, such as retinal tears.
- An abnormal cornea or a disease of the cornea.
- A connective tissue disease that might affect healing of the cornea.
- A job or hobby that could be affected by the side effects of RK. For example, RK may not be a good option for people who drive for a living or who play contact sports.
How Well It Works
RK works well to reduce mild-to-moderate nearsightedness. But it does not always completely fix this problem. You are more likely to still need corrective lenses after surgery if you had moderate-to-high nearsightedness before surgery.
The greatest problems with RK surgery are that:
- The results are hard to predict. Vision is sometimes a few dioptres different than predicted. In contrast, eyeglasses and contact lenses can correct vision within 0.5 dioptre of the desired result.
- The results tend to change over time. RK often causes cause mild farsightedness ( overcorrection). Most people who have RK surgery gradually become more farsighted for at least 8 to 10 years after surgery. This is called the hyperopic shift.
The most common problems from radial keratotomy (RK) include:
- Becoming farsighted after surgery (overcorrection).
- Still being nearsighted after surgery (undercorrection).
- Unstable vision (hyperopic shift).
RK changes the shape of the eye, so you may not be able to wear contact lenses after surgery. Also, RK weakens the cornea and makes it easier to injure. This is not the case with other eye surgeries.
Less common problems include:
- A loss in best corrected vision. Glasses or contacts can correct most eyes to 20/20 vision or better. After RK, a few people have less than 20/20 vision. But the vision loss is usually not severe.
- Irregular astigmatism that causes ghost images or double vision.
- Double vision, trouble seeing how objects are oriented relative to each other, or loss of fine depth perception.
- Glare, especially at night. This is common in the first 3 months after surgery. It may last longer than 6 months. You may see halos or radiating lines around headlights or street lamps. It may be harder to drive at night. Some people need to wear sunglasses or change jobs because of glare.
Very rare problems include glaucoma, puncture or rupture of the cornea, and infection of the cornea. Infection may occur right after the surgery or up to 3 years later.
What To Think About
It's a good idea to talk to your doctor about all your treatment options. These may include PRK, LASEK, epi-LASIK, LASIK, corneal ring implants, and intraocular lens implants. Your doctor can help you understand the risks and benefits of each so you can make the best decision.
Most people choose PRK, LASEK, epi-LASIK, or LASIK surgery instead of RK. But RK still works very well for mild nearsightedness and in some other cases.
RK leaves scars on the cornea. These scars may cause problems if you need another type of eye surgery later in life, such as cataract removal.
RK surgery is an elective procedure. That means it's something that you can choose to have done, but it's not medically needed. It also means that provincial health plans and most private health insurance plans will not pay for the surgery. Cost varies, but it can be high.