Refractive and Corneal Astigmatism After Implantation of a Supraciliary Drainage Device in Microinvasive Glaucoma Surgery

Purpose: To assess the short-term impact of stand-alone MINIject (iSTAR Medical SA) implantation on astigmatism in a single-center retrospective study. Methods: Refractive and corneal astigmatism was investigated based on preoperative and postoperative subjective refraction and Scheimpflug tomography measurements at 3 months (D90) using power vectors: the spherical equivalent M and the Jackson cross cylinder projections to the 0° and 90° (J 0 ) and to the 45° and 135° meridian (J 45 ). Results: A total of 60 eyes with glaucoma or ocular hypertony from 54 patients were included. Refractive cylinder did not change after stand-alone implantation (C D0 = −1.48 ± 1.52 diopters [D] vs C D90 = −1.36 ± 1.20 D, P = .30) and, analogously, no time course was observed in three-dimensional vector analysis ( P > .99). Anterior corneal surface astigmatism showed a near-significant change ( P = .07) in the two-dimensional vector analysis (J 0 ; J 45 ), primarily driven by the J 0 component ( P = .03), whereas the posterior surface remained unaffected ( P = .4). The mean absolute surgically induced astigmatism was 0.78 ± 0.53 D for the anterior surface and 0.22 ± 0.21 D for the posterior surface. Conclusions: Supraciliary MINIject implantation may induce minor short-term changes in anterior corneal astigmatism. However, when implanted as a stand-alone procedure, it does not affect refractive astigmatism. Therefore, astigmatic changes do not require specific emphasis during patient counseling.