Efficacy, Safety, and Survival Rates of IOP-lowering Effect of Phacoemulsification Alone or Combined With Canaloplasty in Glaucoma Patients

Stella N. Arthur, MD, MSPH; Louis B. Cantor, MD; Darrell WuDunn, MD, PhD; Guruprasad R. Pattar, MD; Yara Catoira-Boyle, MD; Linda S. Morgan, CCRC, COA; Joni S. Hoop, CCRC, COA

Disclosures

J Glaucoma. 2014;23(5):316-320. 

In This Article

Abstract and Introduction

Abstract

Purpose. To evaluate efficacy and survival rates of intraocular pressure (IOP)-lowering effect obtained with phacoemulsification (phaco) alone or in combination with canaloplasty (PCP) in patients with open-angle glaucoma (OAG).

Methods. Retrospective chart review of consecutive cases at the Department of Ophthalmology, Indiana University. Visual acuity (VA), IOP, number of medications (Meds), failures, and survival rates of IOP-lowering effect were analyzed. Inclusion criteria were: patients older than 18 years with OAG and cataract. Exclusion criteria were: no light perception vision, prior glaucoma surgery, chronic uveitis, angle-closure glaucoma, and advanced-stage or end-stage OAG. Failure criteria were: IOP>21 mm Hg or <20% reduction, IOP<6 mm Hg, further glaucoma surgeries, and loss of light perception vision.

Results. Thirty-seven patients underwent phaco and 32 patients had PCP. Follow-up was 21.8±10.1 versus 18.8±9.6 months for phaco and PCP, respectively (P=0.21). Age (y) (74.7±9.8 vs. 76.1±8.3, P=0.54), sex (P=81), and laser status (P=0.75) were similar between the groups. Preoperatively, mean±SD logMAR VA (0.5±0.7 vs. 0.5±0.5, P=0.77), IOP (16.2±4.6 vs. 18.2±5.1, P=0.13), and Meds (1.4±1.1 vs. 1.3±0.7, P=0.75) were similar for phaco and PCP, respectively. At 24-month phaco (n=17) and PCP (n=11), respectively, mean±SD were: logMAR VA 0.2±0.2 versus 0.4±0.7, P=0.29; IOP 14.1±4.0 versus 12.9±3.8, P=0.43; and Meds 1.5±1.2 versus 0.3±0.5, P=0.005. Rates of successful IOP lowering without medications for phaco versus PCP at 12 months were 34% versus 75%, respectively (P=0.003).

Conclusions. A combination of canaloplasty with phaco results in a decreased number of glaucoma medications and increased survival rate of IOP-lowering effect compared with phaco alone.

Introduction

Numerous studies demonstrate that phacoemulsification (phaco) may produce long-term reduction of intraocular pressure (IOP) in subjects without glaucoma,[1,2] patients with pseudoexfoliation syndrome,[3,4] or glaucoma patients.[5–8] The effect is thought to be mediated by 3 major mechanisms: hyposecretion of aqueous humor due to production of free radicals or partial ciliary body detachment and irritation; improved uveo-scleral outflow due to increased synthesis of endogenous prostaglandins; and improved trabecular outflow due to increased space in the anterior chamber resulting in increased posterior traction on the scleral spur and expansion of the trabecular meshwork and Schlemm canal (SC), and washing out effect on trabecular meshwork.[8–10]

Canaloplasty is a new surgical technique that provides an alternative to trabeculectomy.[11] The procedure combines nonpenetrating deep sclerotomy with a modified viscocanalostomy utilizing a microcatheter (iTrack & iLumen; iScience International, Menlo Park, CA). Transtrabecular flow is also thought to be enhanced by distending SC 360 degrees with a 10-0 or 9-0 prolene suture. The procedure greatly reduces the likelihood of bleb formation; therefore, the number of postoperative visits may be reduced. Furthermore, there is less long-term risk of bleb-related endophthalmitis associated with canaloplasty.

Although there is a body of literature addressing the efficacy and safety of canaloplasty,[11–16] the data on canaloplasty in combination with phacoemulsification are limited.[15,17] The goal of this study was to evaluate efficacy, safety, and success rates of the IOP-lowering effect obtained with phaco alone or in combination with canaloplasty (PCP) in patients with open-angle glaucoma (OAG).

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