COMBINED INTERRUPTED AND CONTINUOUS VERSUS SINGLE CONTINUOUS ADJUSTABLE SUTURING IN PENETRATING KERATOPLASTY - A PROSPECTIVE, RANDOMIZED STUDY OF INDUCED ASTIGMATISM DURING THE FIRST POSTOPERATIVE YEAR

Objective: To compare postoperative astigmatism induced by two differe nt suturing techniques in penetrating keratoplasty (PKP). Design: A mo nocenter, prospective, randomized clinical trial with a longitudinal I -year follow-up. Participants: A total of 95 eyes undergoing PKP were randomized into 2 groups. Of these, 51 eyes were allocated to the comb ined interrupted and continuous suturing group (ICS) and 44 eyes to th e single continuous adjustable suturing (SCAS) group. Intervention: In the ICS group, suturing was with a combination of 12 interrupted 10-0 nylon and I continuous 11-0 nylon sutures. Eyes in the SCAS group had been sutured with a single running 24-bite 10-0 nylon. Selective sutu re removal started no earlier than 10 weeks after surgery; suture adju stment could start as soon as possible after surgery. Main Outcome Mea sures: Astigmatism was measured by topography, keratometry, and refrac tion at 3-, 6-, 9-, and 12-month postoperative intervals. Results: The difference in mean time of suture manipulation between groups was sig nificant (P = 0.0001), with the SCAS starting earlier. A significant d ecrease in astigmatism occurred by either interrupted suture removal ( 6.69 +/- 3.11 diopter [D] before to 4.76 +/- 2.99 D after, P = 0.0002) or suture adjustment (7.18 +/- 3.12 D before to 4.46 +/- 3.24 D after , P = 0.0001). However, the net astigmatic reduction in the SCAS group was not significantly greater (P = 0.250) than in the ICS group. Vect or change was 7.40 +/- 4.17 D and 6.28 +/- 4.14 D for SCAS and ICS, re spectively (P = 0.13). At no interval (3, 6, 9, or 12 months) was ther e significant difference in astigmatism between the two groups. Refrac tive astigmatism (cyt, D) at 1 year was 2.66 +/- 1.70 for the ICS and 3.12 +/- 2.62 for the SCAS, but there was no significant treatment eff ect (P = 0.945). Furthermore, 66% of the ICS eyes and 58% of the SCAS eyes (P = 0.295) were within the astigmatic target of the study (<3.5 D). Conclusions: Postkeratoplasty astigmatism can be decreased similar ly with either adjustment of a single running suture or selective remo val of interrupted sutures. No advantage of the SCAS over ICS in terms of fewer manipulations or less astigmatism was seen as suggested prev iously.