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.