Different suturing techniques variously affect the regularity of postkeratoplasty astigmatism

This study aimed to determine the effect of various suturing techniques on the regularity of postkeratoplasty astigmatism.

A prospective clinical trial.

Sixty-two consecutive patients undergoing penetrating keratoplasty by the same surgeon (MB) participated.

Each patient was assigned to one of four groups according to the suturing technique used (a = 16 interrupted 10-0 nylon sutures; b = 2 running 10-0 nylon sutures, each with 8 bites; c = 2 running 10-0 nylon sutures, each with 12 bites; d = 2 running 10-0 nylon sutures, each with 16 bites). This was the only parameter permitted to be changed in the standard keratoplasty procedure used for all cases. Corneal topography was performed 1, 3, and 6 months after surgery. The astigmatic patterns seen on the corneal maps then were classified into regular (symmetric or asymmetric bowtie patterns) or irregular (distorted bowtie, multiaxial, or other patterns).

Regularity of postkeratoplasty corneal astigmatism was measured.

At all postoperative examination times, the percentage of irregular astigmatic patterns was highest in group a and lowest in group d (chi-square test: P < 0.005). Groups b and c showed intermediate values. The entity of the astigmatic error as measured by the simulated K-readings of the topographic maps did not differ significantly in the four groups.

A suturing technique using 2 running sutures with 16 bites each can minimize irregular postkeratoplasty astigmatism as long as sutures are in place, when compared with interrupted sutures or double-running sutures of less than 16 bites.