Midterm Results of Microhook ab Interno Trabeculotomy in Initial 560 Eyes with Glaucoma

Abstract

All the 560 glaucomatous eyes of 375 Japanese subjects (181 men, 194 women; mean age ± standard deviation, 76.0 ± 13.2 years) who underwent microhook ab interno trabeculotomy (µLOT) alone (159 eyes, 28%) or combined µLOT and cataract surgery (401 eyes, 72%) performed by one surgeon at Matsue Red Cross Hospital between May 2015 and March 2018 to control intraocular pressure (IOP) were retrospectively assessed. Preoperative and postoperative IOPs, numbers of antiglaucoma medications, the logarithm of the minimum angle of resolution visual acuity (logMAR VA), anterior chamber (AC) flare, visual field mean deviation (MD), and corneal endothelial cell density (CECD) were compared up to 36 months. Surgical complications and required interventions were described. The duration of the follow-up was 405 ± 327 (range, 2-1326) days. The mean preoperative IOP (20.2 ± 7.0 mmHg) and number of antiglaucoma medications (2.8 ± 1.1) decreased to 13.9 ± 4.5 mmHg (31% reduction, p < 0.0001) and 2.5 ± 1.0 (11% reduction, p < 0.0001), respectively, at the final visit. After combined surgery, compared with preoperatively, the final VA improved 0.11 logMAR (p < 0.0001), AC flare increased 4.5 photon counts/msec (p = 0.0011), MD improved 0.6 decibel (p < 0.0001), and the CECD decreased 6% (p < 0.0001). Layered hyphema (172 eyes, 31%) and hyphema washout (26 eyes, 5%) were the most common postoperative complication and intervention, respectively. At the final visit, 379 (69%) eyes achieved successful IOP control of ≤18 mmHg and ≥20% IOP reduction, and 349 (64%) eyes achieved successful IOP control of ≤15 mmHg and ≥20% IOP reduction. Older age, steroid-induced glaucoma, developmental glaucoma, and the absence of postoperative complications were associated with lower final IOP; exfoliation glaucoma, other types of glaucoma, and higher preoperative IOP were associated with higher final IOP. µLOT has a significant IOP-lowering potential in patients with glaucoma, and improves visual function when combined with cataract surgery.

Keywords: Tanito microhook (TMH); minimally invasive glaucoma surgery (MIGS); surgical complication; surgical efficacy.

Conflict of interest statement

The microhooks used were co-developed by Masaki Tanito, and Inami & Co., Ltd. (Tokyo, Japan). Tanito receives royalties from Inami & Co., Ltd. The company had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. Other authors report no conflicts of interest in this work.

Figures

Figure 1

Success rate of intraocular pressure (IOP) control after microhook trabeculotomy by survival curve analysis. For the survival curve analysis, the uncensored date was defined as the postoperative period of later than 90 days and the day when the IOP level exceeded 18 mmHg (a,c) or 15 mmHg (b,d), IOP reduction of less than 20% (a,b), or exceeding the baseline IOP (c,d) with antiglaucoma medication, additional glaucoma surgery (a–d), or loss of light perception (a–d); the cases other than those that were uncensored were regarded as censored cases at the final visit. The dotted lines indicate the ranges of the 95% confidence intervals of the survival analysis. Y, years.

Figure 2

The cumulative incidence of additional glaucoma surgery after microhook trabeculotomy by survival curve analysis. For the survival curve analysis, the uncensored date was defined as the day when additional glaucoma surgery was performed; the cases other than those that were uncensored were regarded as censored at the final visit. The dotted lines indicate the ranges of the 95% confidence intervals of the survival analysis. Y, years.