Comparison of surgically induced astigmatism following different glaucoma operations

Abstract

AimTo compare surgically induced astigmatism (SIA) among glaucomatous eyes treated with trabeculectomy (LEC), EX-PRESS® shunt (EXP), ab externo trabeculotomy (exLOT), or microhook ab interno trabeculotomy (μLOT).Subjects and methodsEighty right eyes of 80 subjects who underwent LEC (n=20), EXP (n=20), exLOT (n=20), or μLOT (n=20) were included. The dataset including the best-corrected visual acuity (BCVA), intraocular pressure (IOP), and keratometry recordings preoperatively and 3 months postoperatively was collected by chart review. The means of the vector magnitude, vector meridian, and arithmetic magnitude of the preoperative and postoperative astigmatism and SIA were calculated. The correlations among the SIA magnitude, postoperative BCVA, and IOP were assessed.ResultsThe mean astigmatic arithmetic magnitudes did not differ significantly (P=0.0732) preoperatively among the four groups, but the magnitude was significantly (P=0.0002) greater in the LEC group than the other groups postoperatively. The mean SIA vectors were calculated to be 1.01 D at 56°, 0.62 D at 74°, 0.23 D at 112°, and 0.12 D at 97° for the LEC, EXP, exLOT, and μLOT groups, respectively. The mean SIA arithmetic magnitudes were significantly (P<0.0001) greater in the LEC group than the other groups. Three months postoperatively, the SIA magnitude was correlated positively with the logarithm of the minimum angle of resolution (logMAR) BCVA (r=0.3538) and negatively with the IOP (r=−0.3265); the logMAR BCVA was correlated negatively with the IOP (r=−0.3105).ConclusionEXP, exLOT, and μLOT induce less corneal astigmatism than LEC in the early postoperative period.

<p>Comparison of anterior chamber flare among different glaucoma surgeries</p>

“…The decimal BCVA was converted to the logarithm of the minimum angle of resolution VA, the IOP by Goldmann applanation tonometry, and the ACF by the FM-600 laser flare meter (Kowa, Nagoya, Japan). All surgical procedures have been described previously 9–11…”

Ab-interno trabeculotomy-related glaucoma surgeries

“…[8] The smaller surgical incisions created in the ocular surface with ab-interno trabeculotomy-related procedures cause less induced postoperative astigmatism than astigmatism that develops following trabeculectomy. [15] Direct visualization of the anterior-chamber angle achieved using a gonioprism lens during ab-interno trabeculotomy facilitates easier identification of Schlemm's canal compared with identification of the anterior-chamber angle under the scleral flap during conventional ab-externo trabeculotomy. The extent of the trabeculotomy (90–120°) the conventional ab-externo trabeculotomy [Figure 4a], the Trabectome procedure, and the Kahook Dual Blade [Figure 4b] is wider, i.e., 180–240° for microhook ab-interno trabeculotomy [Figure 4c] and 360° with suture trabeculotomy when a suture is inserted successfully into the entire circumference of Schlemm's canal [Figure 4d].…”

Observation of Gonio Structures during Microhook Ab Interno Trabeculotomy Using a Novel Digital Microscope with Integrated Intraoperative Optical Coherence Tomography

“…We initially reported a case of both eyes of one patient with steroid-induced glaucoma who underwent a novel ab interno trabeculotomy, which we referred to as microhook ab interno trabeculotomy (μLOT) [3]. Because of the substantial IOP decrease in that case, we began to perform the procedure in other cases and reported the early postoperative results and safety profile of μLOT [4][5][6][7]. e features of μLOT, which include conjunctival and scleral sparing with the ab interno technique, short surgical time, moderate IOP reduction, and no bleb-related complications, fulfill the conditions of minimally invasive glaucoma surgery (MIGS) [8].…”