Radial Keratotomy (RK)

RK is a surgical procedure to correct nearsightedness (myopia) and astigmatism. Under topical anaesthetic, a diamond knife is used to make small incisions on the cornea (the front surface of the eye). These cuts cause the cornea to flatten and as a result, the focusing of light moves back towards the retina of the eye.

What is Photorefractive Keratectomy (PRK)

A recent innovation is the use of the Excimer laser to perform photo-refractive keratotomy or PRK. In this procedure an excimer laser is used to vaporize a fine layer of the cornea, thus flattening it out and correcting the vision. This procedure is relatively new and considered experimental by Health and Welfare Canada.

What are the expected results of RK/PRK?

Both usually reduce nearsightedness but the results are unpredictable for each individual. Generally only patients who are mildly nearsighted may be able to see clearly at far distances without glasses or contact lenses after the procedure. Others may reduce their nearsightedness significantly, but may still need prescription lenses, although their lenses may not be as strong.

What are the risks or complications?

There are three significant risks to RK: the incision weakens the cornea, making a cornea rupture a possibility after an eye injury; there is a long term risk of corneal disease development; and cataract surgery may be jeopardized later in life. With PRK, some patients may experience scarring of the corneal surface which could lead to a second treatment.

Complications such as corneal perforations and an increased risk of long term infection have been experienced by patients undergoing the procedures. Other possibilities include unpredictable results; fluctuations in vision during the day; and an increased difficulty in fitting contact lenses.

Does RK or PRK eliminate the need to wear glasses or contact lenses?

Other vision problems requiring treatment with prescription lenses may exist along with nearsightedness. Two of the most common are astigmatism and presbyopia {a loss of focusing ability of the eye's lens that occurs usually after age 40 and affects reading vision). Even with RK/PRK, most people eventually will need glasses or contact lenses for other vision problems.

If you are interested in further information or an examination to determine if you are a candidate for RK/PRK, please call our office at (416) 486-6084. Brochures and video on RK/PRK are also available at our office.

Lasik has become the treatment of choice. See one of the doctors at The Toronto Eye Clinic for the laser clinics and types of procedures we recommend.  Also see section on this web site called

  • Laser Vision Care FAQ