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Spherical component may account for refractive regression after LASIK
Refractive regression after LASIK is more closely related to the spherical component than the cylindrical component in moderately to highly astigmatic eyes, according to a study.
“This suggests that refractive regression occurs by corneal steepening in the spherical component and that astigmatic regression does not occur, even in moderately to highly astigmatic eyes,” the study authors said.
The retrospective case series analyzed 48 eyes of 35 consecutive patients who had wavefront-guided LASIK to correct moderate to high astigmatism of 2 D or more. The patients had a mean age of 34 years, a mean preop spherical error of –5.10 ± 2.11 D, and a mean preop cylindrical error of –2.74 ± 0.99 D. They were examined at 1 week and 1, 3, 6 and 12 months postop.
Mean spherical refraction changed from 0.38 ± 0.80 D at 1 week to –0.13 ± 0.90 D at 1 year, which was significant (P < .001). Mean cylindrical refraction changed from –0.67 ± 0.54 D at 1 week to –0.63 ± 0.63 D at 1 year, which was not significant.
“There were significant increases in the flattest and steepest keratometry readings at 1 week and at 1 year,” the study authors said. “However, no significant change in corneal astigmatism was found at either time point.”