Radial Keratotomy
A form of refractive surgery that corrects myopia.Radial keratotomyRead more reduces myopia by flattening the cornea(the transparent part of the eye which covers pupil and iris). This reduces the focusing power of the cornea allowing light to focus further back onto the retina (or at least closer to it), forming a clearer image. Every radial keratotomy is different from another. Various tests are required to obtain information that might alter the procedure for each operation. This includes information about how much myopia or astigmatism is present, the degree of corneal curvature, and the thickness of the cornea. A thorough examination of your eyes is also done to determine if there are any medical problems that might interfere with surgery. See photos of radial keratotomy(post operative) Also, RK does not treat hyperopia.
Eligibility
You may not be eligible for RK if you have:
- Nearsightedness that is still getting worse (such as in children and teenagers).
- Pathological myopia, in which the eyeball fails to stop growing longer.
- Degenerative changes caused by severe nearsightedness (high myopia), such as retinal tears.
- An abnormality or disease of the cornea.
- A 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 participate 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 very rarely may cause the tiny incisions to rupture.
Procedure
While you are awake and pain-free (using local anesthesia), a series of delicate incisions are made around the cornea. This flattens the center of the cornea in order to change the focus of light rays on the retina. Each eye is operated on separately, and on different days. Radial incisions are made facing inwards and perpendicular to cornea. As the incisions heal, the center of the cornea flattens and refractive error is modified. The procedure is an ancestor of modern LASIK surgery, and is rarely performed today due to its unpredictability and tendency for inaccuracies.
Benefits
- Very safe
- Predictable for low range of Myopia
- Rapid results
Risks Factors concerning Radial Keratotomy
RK may result in:
- Halos or starburst patterns around lights at night
- Structural weakening of the eye (resulting in a risk of rupturing with blunt trauma). Note: this is largely hypothetical.
- More incisions need to be made for patient's that are more nearsighted
- cataract a clouding of the lens of the eye, resulting in partial or total loss of vision
- lasting pain
- rips along an incision, especially after being hit in the head or eye
- 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. This is not the case with LASIK or PRK.
- A loss in best corrected vision. Before RK, most eyes can be corrected with glasses or contacts to 20/20 vision or better. Up to 3% of people who have RK have best corrected vision of less than 20/20 after surgery.1 However, the vision loss is usually not severe.
- Irregular astigmatism that causes ghost images or double vision.
- Double vision, difficulty seeing how objects are oriented relative to each other, or loss of fine depth perception.
- Glare, especially at night. Glare is common in the first 3 months after surgery and may last longer than 6 months. It does not appear to be a significant problem, but 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, including:
- Puncture (perforation) of the cornea.
- Infection of the cornea (bacterial keratitis). This may occur immediately after the surgery or up to 1 to 3 years later as the cornea continues to heal.
- Rupture of the cornea at the kerototomy scars after a severe blow to the eye
- Glaucoma
The chances of complications are reduced when the surgery is done by an ophthalmologist with a lot of experience in RK. Younger patients also tend to heal faster.
After care
An eye patch or dark glasses are worn for several days. The final outcome of your corrected vision can take up to several months. Advances in refractive surgery are being made rapidly. New procedures that are slowly replacing radial keratotomy are being used more frequently. Use of the Excimer laser has greatly improved refractive surgery. Consultation with a specialist is advised before deciding on a particular procedure.
History
Discovered by Svyatoslav Fyodorov during an attempt to remove glass from a young patient's eye. In order to remove the glass, Dr. Fyodorov made radial incisions in the cornea in a pie-like pattern to gain access to the broken shards. After the cornea healed, the patient's eyesight was, remarkably, improved.
Alternatives
Radial Keratotomy has been almost completely replaced in recent years by PRK, LASIK, and Intacs due to their higher degree of accuracy
