Radial keratotomy clear zone diameter errors

PURPOSE: To examine the variability of achieved clear zone diameters follow ing radial keratotomy and to determine if refractive outcomes are correlate d to clear zone diameter errors. METHODS: Twenty-six patients with radial keratotomy (51 eyes) were studied retrospectively. The central clear zone diameter for each radial incision m eridian was measured using a slit-lamp and a photograph. The achieved clear zone diameters were statistically compared to the intended clear zone size s and to the refractive outcomes. RESULTS: Twenty-nine of the 51 eyes met various exclusion criteria. Ninety individual slit-lamp clear zone measurements were obtained for the remainin g 22 eyes. Sixty-two of 90 (69%) achieved clear zone diameters were more th an 0.25 mm different than the intended clear zone size. A maximum differenc e of +/-0.80 mm from the intended clear zone marker size was observed. The average clear zone diameter error did not statistically differ between the three refractive outcome groups (undercorrection, emmetropia, and overcorre ction). CONCLUSIONS: In selected cases of centripetal radial keratotomy, the achiev ed clear zone diameter can vary widely hom the intended clear zone size des pite extensive surgeon experience.