Trabectome Versus Trabeculectomy With Mitomycin C in Patients With Open Angle Glaucoma

Prospective Randomized Controlled Trial of Trabectome Versus Trabeculectomy With Mitomycin C in Patients With Open Angle Glaucoma

The purpose of this study is to compare the efficacy and safety of Trabectome versus Trabeculectomy with adjunctive Mitomycin C, combined with cataract surgery, in patients with open angle glaucoma.

Background: Trabeculectomy with adjunctive use of Mitomycin C (Trab MMC) is the standard incisional procedure to lower intraocular pressure (IOP) in adults with open angle glaucoma (OAG). Trab MMC has been shown to effectively lower IOP, however, it can be associated with a number of serious complications, such as hypotony maculopathy, choroidal effusion or hemorrhage, and endophthalmitis, as well as less serious complications that may affect vision related quality of life such as bleb dysesthesia. A newer technology, referred to as the Trabectome (NeoMedix Corp., San Juan Capistrano, CA), removes an arc of trabecular meshwork and inner wall of Schlemm's canal with microcautery and appears to lower IOP effectively with fewer and less serious complications than Trab MMC. However, more studies are needed to determine the long term safety and efficacy of this relatively new procedure. In addition, for OAG patients with visually significant cataracts, either Trab MMC or Trabectome can be combined with cataract surgery. Study Objective: To compare the efficacy and safety of Trabectome versus Trab MMC, in combination with cataract extraction by phacoemulsification and intraocular lens implant, for control of IOP in OAG, including pseudoexfoliative glaucoma. Methods: Single center, single surgeon, prospective randomized controlled trial. A total of 52 eligible participants, 26 per study arm would need to be recruited for 90% power. One eye per study patient will be enrolled and randomized to Trabectome combined with cataract surgery (Trabectome-IOL) or Trab MMC combined with cataract surgery (Trab-IOL). Postoperative visits will take place at the discretion of the surgeon but will include at least visits at day 1, week 1, and months 1, 3, 6, and 12. Postoperative glaucoma medications will be added in a stepped regimen as appropriate, along with additional laser or surgical procedures if needed. Current Study Status: The clinical trial was terminated early due to slow recruitment and clearer indications for each technique over time leading to lack of clinical equipoise essential for patient randomization/recruitment. This had been discussed and agreed upon with our data safety monitoring board. A total of 19 participants were recruited with followup to one year. Study analysis is pending.

Trabectome removes an arc of trabecular meshwork and inner wall of Schlemm's canal to enhance aqueous outflow through natural drainage pathways. Trabectome will be done first, followed by cataract surgery because Trabectome requires a clear view through the cornea using a goniolens, and this view may be compromised after cataract surgery.

Trabeculectomy bypasses the normal aqueous outflow channels of the eye and creates an external filtration pathway (called a filtering bleb) for aqueous to drain and be reabsorbed back into the circulation. Mitomycin C is an agent used during this procedure to decrease scar formation around the new passage. Cataract surgery will be done first, followed by Trabeculectomy with Mitomycin C.

Inclusion Criteria: Age 40-85 years Open angle glaucoma (including pseudo exfoliative glaucoma) Open angles (≥ Shaffer grade II) Inadequately controlled IOP requiring surgical intervention Visually significant cataract Willing to complete quality of life questionnaires Capable of informed consent and available for at least 1 year follow-up Exclusion Criteria: Any form of angle closure glaucoma Secondary open angle glaucomas Absence of clear angle landmarks on gonioscopy Other ocular disease that may affect assessments of visual acuity, visual field, or accurate tonometry Previous angle surgery or filtering procedure Steroid use within the preceding 3 months Presence of significant co-morbidities

Hu K, Shah A, Virgili G, Bunce C, Gazzard G. Ab interno trabecular bypass surgery with Trabectome for open-angle glaucoma. Cochrane Database Syst Rev. 2021 Feb 4;2(2):CD011693. doi: 10.1002/14651858.CD011693.pub3.

Hu K, Gazzard G, Bunce C, Wormald R. Ab interno trabecular bypass surgery with Trabectome for open angle glaucoma. Cochrane Database Syst Rev. 2016 Aug 15;(8):CD011693. doi: 10.1002/14651858.CD011693.pub2.