Purpose of review: The Primary Tube Versus Trabeculectomy (PTVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube shunt surgery and trabeculectomy with mitomycin C (MMC) in eyes without previous incisional ocular surgery. This article reviews results from the PTVT Study and suggests how they may be translated to clinical practice.
Recent findings: Tube shunt surgery had a higher failure rate than trabeculectomy with MMC in the PTVT Study, and the difference was statistically significant at 1 year but not at 3 years and 5 years. Both surgical procedures reduced intraocular pressure (IOP) to the low teens throughout 5 years of follow-up. Mean IOPs were lower after trabeculectomy with MMC compared with tube shunt implantation, and the differences were statistically significant during the first postoperative year and at 3 years. The greater IOP reduction after trabeculectomy with MMC was achieved with significantly fewer glaucoma medications relative to tube shunt placement. Surgical complications were common in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was significantly higher after trabeculectomy with MMC than tube shunt surgery. The rates of late postoperative complications, cataract progression, and vision loss were similar with both surgical procedures. Serious complications producing vision loss and/or requiring a reoperation to manage the complication developed more frequently after trabeculectomy with MMC compared with tube shunt surgery, and the difference was statistically significant at 1 year but not at 3 years and 5 years postoperatively.
Summary: Tube shunt implantation and trabeculectomy with MMC are both viable surgical options for managing glaucoma in patients without previous incisional ocular surgery. Results from the PTVT Study support further expansion of tube shunt use beyond refractory glaucomas.
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