Baseline Risk Factors Linked to Chronic Hypotony After Tube Shunt Surgery,: Study

Researchers have found in largest prospective dataset on tube shunt outcomes that Chronic hypotony is a rare complication of tube shunt surgery that often leads to reduced visual acuity and the key baseline risk factors include Baerveldt implant use, uveitic glaucoma, and poor initial vision.. 

The study was performed to describe the incidence and risk factors for chronic hypotony following tube shunt surgery. It consisted of a pooled analysis of three independent, multicenter randomised clinical trials. There were 621 patients with medically uncontrolled glaucoma, including 276 from the Ahmed Baerveldt Comparison Study, 238 from the Ahmed Versus Baerveldt Study, and 107 from the tube group of the Tube Versus Trabeculectomy Study. Enrolled patients had been randomised to placement of either an Ahmed glaucoma valve (model FP7) or a Baerveldt glaucoma implant (model 101-350). Baseline and follow-up data were obtained on a per-patient level and pooled. The associations between baseline risk factors and chronic hypotony were explored using a Cox proportional hazards regression model. The main outcome was chronic hypotony, defined as intraocular pressure (IOP) ≤ 5 mmHg on 2 consecutive visits after 3 months, tube ligation, or implant removal for hypotony.