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Comparison of surgically induced astigmatism following different glaucoma operations

Authors Tanito M, Matsuzaki Y, Ikeda Y, Fujihara E

Received 26 September 2017

Accepted for publication 26 October 2017

Published 28 November 2017 Volume 2017:11 Pages 2113—2120


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Scott Fraser

Masaki Tanito, Yukari Matsuzaki, Yoshifumi Ikeda, Etsuko Fujihara

Division of Ophthalmology, Matsue Red Cross Hospital, Matsue, Japan

Aim: To 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 methods: Eighty 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.
Results: The 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).
Conclusion: EXP, exLOT, and µLOT induce less corneal astigmatism than LEC in the early postoperative period.

Keywords: SIA, trabeculectomy, EX-PRESS shunt, ab externo trabeculotomy, microhook ab interno trabeculotomy, MIGS

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