To investigate the long term intraocular pressure (IOP) changes and glaucoma incidence after pars plana vitrectomy

In this historical cohort study, patients undergone vitrectomy on one eye who met the inclusion/exclusion criteria were enrolled. > 6mmHg rise in IOP was considered as to be significant. Patients who needed glaucoma medication/surgery or > 0.2 cup/disc ratio increment were considered to have developed open angle glaucoma( OAG).

A total of 239 patients were enrolled. Mean follow up period was 20.6 months (3-96 months). Mean baseline IOP was 13.5mmHg and the final IOP was 16mmHg. Significant IOP rise occurred in 37 study eyes (15%) and 7 fellow eyes (3%, P<0.001). post operative lens satus (phakic, aphakic or pseudophakic), indication of vitrectomy and number of operations were not associated with IOP rise. Silicon oil (SO) injection showed a tendency to rise IOP although it wasn’t significant (P=0.05). OAG occurred in 17 study eyes (8%) while non of the fellow eyes developed glaucoma. Eyes with >1 vitrectomies showed a higher incidence of OAG (P<0.0001).

Vitrectomy can increase the risk of IOP rise. Repeated vitrectomies are a risk factor of OAG. SO injection, post operative lens status, and indication of vitrectomy don’t increase the risk.