Glaucoma drainage device surgery after vitreoretinal surgery: incidence and risk factors

Purpose: The initial success of vitreoretinal surgery can be annihilated by an acceleration of preexisting glaucoma or the development of secondary glaucoma. Aim of this study was to determine the incidence of and risk factors for medically uncontrollable glaucoma after vitreoretinal surgery.

Methods: Case-control study amongst patients who underwent vitreoretinal surgery at the University Medical Center Groningen between 1991 and 2011 (in total 14 942 interventions). Cases were all patients who received a glaucoma drainage device after vitreoretinal surgery. Controls were a subset of the patients who underwent vitreoretinal surgery without a subsequent drainage device. Cases and controls were matched (three controls per case) with regard to the year of the (first) vitreoretinal intervention. The incidence rate was calculated from the number of cases and the number of person-years corresponding to all vitreoretinal interventions performed in the study period. Risk factors were analysed with logistic regression.

Results: Ninety-five cases were identified after a follow-up of 101 961 personyears (one per 1000 person-years). Cases were younger (p = 0.017), were more often men (p = 0.035), underwent more interventions (p <0.001) or were treated with silicone oil (p = 0.021), had a higher intra-ocular pressure 1 week after the intervention (p <0.001) and had more often a history of glaucoma or ocular hypertension (p <0.001).

Conclusion: Glaucoma after vitreoretinal surgery that requires a glaucoma drainage device is not very common and patients who need a device differ from those who do not. This gives the opportunity to monitor certain subgroups more closely.