Drainage device implantation riskier than trabeculectomy

The risk of adverse events following implantation of a glaucoma drainage device (GDD) is higher than the risk following either primary trabeculectomy (PT) or trabeculectomy with scarring (TS), according to results of a study published in the July 2008 issue of Ophthalmology.

Frank A. Sloan, PhD of the Center for Health Policy, Duke University, North Carolina, US and colleagues conducted a retrospective, longitudinal cohort analysis of subjects (aged ≥68 years) undergoing PT, TS or GDD implantation between 1994–2003, with follow-up to 2005, to determine rates of postoperative adverse outcomes.

Retinal detachment, endophthalmitis and suprachoroidal haemorrhage were classified as severe complications; choroidal detachment, corneal oedema and hypotony were classified as less serious outcomes.

At the one year follow-up point, severe adverse events in the GDD implantation, TS and PT subject groups were 2.0%, 1.3% and 0.6%, respectively; rates of subjects developing less serious adverse events and low vision/blindness were higher in the GDD group than in the TS and PT groups. After controlling for demographic factors, differences were reduced but not to a statistically significant degree.

Regardless of controlling for demographic factors, the rates of adverse events across the spectrum of severity were slightly higher for patients undergoing GDD implantation than TS or PT surgery.