Effect of incision direction on refractive outcome after radial keratotomy.

PURPOSE: To determine whether the direction of radial keratotomy (RK) incisions (centripetal versus centrifugal) affects refractive outcome. SETTING: Private ophthalmology office. METHODS: The database of a single surgeon was retrospectively reviewed. Stepwise regression was used to select significant predictors of refraction change in the population. In addition to incision direction, variables evaluated were optic zone diameter, number of incisions, patient age, corneal curvature, and planned incision depth. RESULTS: All variables except planned incision depth and corneal power affected refractive outcome. After controlling for number of incisions, optic zone diameter, and patient age, centripetal incisions decreased myopia 0.87 diopters more than centrifugal incisions. CONCLUSIONS: Our results, consistent with previous investigations, found that number of incisions, optic zone diameter, and patient age were significant predictors of refractive outcome after RK. Incision direction was also a significant predictor by itself or coupled with optic zone diameter and number of incisions, with the centripetal incision decreasing myopia more.