Radial keratotomy

Radial keratotomy
Intervention
Schematic diagram of RK, with incisions drawn in orange
ICD-9-CM	11
MeSH	D007646
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Radial keratotomy (RK) is a refractive surgical procedure to correct myopia (nearsightedness) that was developed in 1974, by Svyatoslav Fyodorov, a Russian ophthalmologist. Though it has been largely supplanted by newer operations, such as photorefractive keratectomy, LASIK, Epi-LASIK and the phakic intraocular lens, RK remains popular for correction of astigmatism in certain patients.

Beginning in 1936, Japanese ophthalmologist Tsutomu Sato conducted research in anterior and posterior keratotomy, an early form of refractive surgery that attempted to treat , myopia and astigmatism by making incisions in the cornea.

In 1974, Svyatoslav Fyodorov removed glass from the eye of a boy who had been in an accident. The boy, who required eyeglasses for correction of myopia caused by astigmatism, fell off his bicycle. His glasses shattered on impact, and glass particles lodged in both eyes. To save the boy's vision, Fyodorov performed an operation which consisted of making numerous radial incisions extending from the pupil to the periphery of the cornea in a radial pattern like the spokes of a wheel. After the glass was removed by this method and the cornea healed, Fyodorov found that the boy's visual acuity had improved significantly.

In RK, incisions are made with a diamond knife. Incisions that penetrate only the superficial corneal stroma are less effective than those reaching deep into the cornea, and consequently, incisions are made quite deep. One study cites incisions made to a depth equivalent to the thinnest of four corneal-thickness measurements made near the center of the cornea. Other sources cite surgeries leaving 20 to 50 micrometres of corneal tissue unincised (roughly equivalent to 90% of corneal depth, based on thickness norms).