Effects of astigmatic keratotomy combined with scleral tunnel incisions for the treatment of high astigmatism after penetrating keratoplasty.

The present study aimed to evaluate the efficacy, predictability and safety of astigmatic keratotomy (AK) combined with scleral tunnel incisions in the treatment of high astigmatism after penetrating keratoplasty (PKP). Paired AK combined with scleral tunnel incisions was performed at the steep astigmatic meridian in 8 eyes of 8 patients with high keratometric astigmatism [>5.0 diopters (D)] after PKP. Pre- and post-operative parameters, including uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction and keratometric astigmatism were evaluated. The Alpins method for vector analysis was used to evaluate the changes in keratometric astigmatism. The results indicated a statistically significant reduction in the mean keratometric astigmatism from 8.16 +/- 3.02 D pre-operatively to 2.28 +/- 1.07 D at 3 months postoperatively. The mean UCVA improved from 0.95 +/- 0.24 logarithm of the minimum angle of resolution (logMAR) pre-operatively to 0.61 +/- 0.17 logMAR at 3 months postoperatively (P<0.05). The mean BCVA improved from 0.41 +/- 0.18 logMAR pre-operatively to 0.26 +/- 0.12 logMAR at 3 months postoperatively (P>0.05). Between 3 and 6 months after the surgery, the keratometric astigmatism remained stable. Alpins vector analysis demonstrated the relative predictability of this combined surgical treatment. The surgically induced astigmatism was significantly correlated with the target induced astigmatism (r=0.76, P<0.05). None of the patients had any severe complications. The present study indicated that AK combined with scleral tunnel incisions is an effective, relatively predictable and safe treatment for high astigmatism after PKP.