title: Factors affecting predictability of radial keratotomy.
abstract: A major criticism of radial keratotomy (RK) has been its lack of predictability, a lack due in large measure to the use of simple correlational statistics assessing the relationship between refractive result and each predictor-variable being evaluated separately. This report utilizes multivariate analysis in an attempt to account for the effects of a number of predictor-variables simultaneously. Variables studied are patient age, optical zone size, number of incisions, mean incision depth, preoperative average keratometry, preoperative average applanation tension, patient sex, and age-sex interrelationship. The area of the optical clear zone selected by the surgeon was found to be the most important factor determining refractive change as a result of RK, explaining one-quarter to one-half of the variability of the procedure. The effects of the other factors and the limitations of the method are discussed. Although this method cannot produce a fully predictive equation, we believe this analysis can serve as a good starting point for beginning RK surgeons and a method by which experienced RK surgeons can improve their techniques.
mesh_terms: D000328:Adult; D000367:Age Factors; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D012044:Regression Analysis; D012737:Sex Factors