The Effect of Trabeculectomy on Astigmatism

Abstract

Trabeculectomy induced a small but statistically significant shift in astigmatism with-the-rule after 6 months. The spherical equivalent did not change compared with the preoperative value. Most often, glasses will not need to be changed after trabeculectomy.

Trabeculectomy With Moorfields Conjunctival Closure Technique Offers Safety Without Astigmatism Induction

“…In keeping with earlier published results, our study could identify a statistically significant change in postoperative corneal astigmatism. 4 Vector analysis confirmed a significant change with a tendency toward WTR astigmatism, which persisted throughout the follow-up period. These observations are comparable to previously published results by our research group using a different conjunctival closure technique with only 2 purse string sutures without corneal grooves.…”

“…Rosen and colleagues found no influence of scleral flap suture lysis on corneal astigmatism and this finding was confirmed by our previous study. 4,23 A follow-up study, with the possible use of corneal topography and decreased measurement interval, could provide further insights as to the optimal strategy for managing postoperative corneal astigmatism and the role of corneal and scleral suture removal.…”

“…10,11 Sample sizes were calculated from the data of our previous report on astigmatic shift following trabeculectomy. 4 Sample size based on a power of 80% and a type I error occurrence of 5% was estimated to be at least 20 subjects for a change in corneal astigmatic power of 0.5 D. This number was doubled to allow for subgroup comparison and a 10% drop out was anticipated.…”

“…), according to a modified Moorfields technique described in detail in our previous paper on this subject. 4 The only difference was the conjunctival closure technique using 4 fixed nylon 10/0 sutures with nods embedded in half-thickness corneal grooves (2 purse string sutures on the edges of the incision and 2 mattress sutures in the middle) ( Fig. 1).…”

“…Surgery was performed using a conjunctival closing technique with 2 laterally placed purse string sutures as described in the "Moorfields Safe Trabeculectomy Technique" described by Khaw and colleagues. [4][5][6] Recently, the conjunctival suturing technique was further modified into the "corneal groove closure" technique consisting of 2 purse string and 2 mattress sutures embedded in corneal grooves. The addition of 2 mattress sutures has the advantage of reducing postoperative bleb leakage and eliminating central conjunctival retraction.…”