Factors that influence the surgical effects of astigmatic keratotomy after cataract surgery.

OBJECTIVE

To determine the factors affecting the surgical effect of astigmatic keratotomy (AK) when against-the-rule astigmatism is present following cataract surgery.

DESIGN

Prospective interventional noncomparative case series.

PARTICIPANTS

Twenty eyes of 19 patients from four medical centers who had against-the-rule astigmatism following cataract surgery.

INTERVENTION

AK with a 6 mm optical zone, two linear 3-mm length incisions (T-cut) and a depth of 90% of the central thickness was performed on all subjects.

MAIN OUTCOME MEASURES

Vector analysis of astigmatic correction. Multiple regression analysis for seven covariates including age, spherical equivalent of the manifest refraction, preoperative astigmatism, corneal diameter, corneal thickness, mean radius of corneal curvature and axial misalignment.

RESULTS

Multiple regression analysis showed that the preoperative astigmatism (p = 0.014) and the axis deviation (p = 0.005) were significantly correlated with the surgical effects.

CONCLUSIONS

Even with a uniform surgical procedure, the surgical effects of AK in eyes with against-the-rule astigmatism can be affected by the amount of preoperative astigmatism and the intraoperative axis misalignment. Adding the amount of preoperative astigmatism to the nomogram and improvement of surgical procedures will be required to obtain better surgical predictability of AK following cataract surgery.