LXII Edward Jackson lecture: open angle glaucoma after vitrectomy.

PURPOSE: To present data and an hypothesis for the late development of open angle glaucoma (OAG) after vitrectomy.
DESIGN: A retrospective observational case series.
METHODS: The records of 453 eyes that had undergone vitrectomy were reviewed for postoperative OAG. Eyes with confounding factors were excluded. Sixty-eight eyes of 65 patients that underwent routine vitrectomy were followed for a mean of 56.9 months (range, seven to 192 months). For the main outcome measures, patients were classified into three groups: patients with suspected glaucoma, patients in whom glaucoma developed after the operation, and patients with pre-existing glaucoma.
RESULTS: In glaucoma suspects, the mean intraocular pressure was significantly higher in the operated eye compared with the fellow eye (P = .0001). In eyes with new onset glaucoma, 23 of 34 eyes (67.6%) had it in the vitrectomized eye only. In phakic eyes, the time interval between vitrectomy and the development of glaucoma (mean, 45.95 months) was significantly longer than eyes that were nonphakic at the time of vitrectomy (mean, 18.39 months; P = .0115). When the interval between cataract surgery in phakic eyes to the development of glaucoma was compared with the interval from vitrectomy to glaucoma diagnosis in the nonphakic group, the difference was not statistically significant. In eyes with glaucoma before the operation, the mean number of antiglaucoma medications that were required to control the intraocular pressure was significantly higher in the vitrectomized eye, compared with the fellow eye (2.9 medications +/- 1.2 vs 2.0 medications +/- 1.4; P = .0215; n = 14).
CONCLUSION: There is an increased risk of OAG after vitrectomy. The presence of the lens may be protective. In established OAG before the operation, the number of antiglaucoma medications may increase after surgery. Oxidative stress is hypothesized to have a role in the pathogenesis.