Radial keratotomy (RK) is a non-laser refractive surgery procedure that gained popularity in the 1980s for the correction of myopia (nearsightedness), and is now obsolete.
In RK, the surgeon uses a hand-held, bladed instrument to make a series of radially-arranged incisions (cuts) in the intermediate and peripheral zones of the cornea. The incisions form a pattern like the spokes on an old fashioned wagon-wheel, with circular central zone (the hub of the wheel) left untouched. As few as 4 or as many as 12 or more incisions are used, depending on the severity of the myopia being treated.
The incisions made in RK must penetrate approximately 90% of the total corneal thickness in order to be effective. As the cuts heal, they flatten the curvature of the cornea, thereby correcting nearsightedness.
Since the corneal incisions in RK are deep, a perforation of the eye is possible if the blade cuts too deeply. In this instance, fluid inside the eye could leak outward, creating a risk of an eye infection or other serious complications. The surgeon may need to apply temporary stitches over the wound to stop the leak, should a perforation occur during the procedure.
Though RK was effective in correcting myopia, it had a number of additional risks and shortcomings, including: unpredictable outcomes, loss of some of the vision correction over time (regression), glare and halos at night, and visual fluctuations.
With the introduction of the excimer laser for refractive surgery in the early 1990s and its promise of safer procedures and more precise and predictable treatments, RK was abandoned as a treatment option by most refractive surgeons. RK no longer meets the standard of care in modern refractive surgery is rarely used today.