Long‑Term Intraocular Pressure Changes after Pars Plana Vitrectomy: An 8‑Year Study

Purpose: To investigate the long‑term changes of intraocular pressure (IOP) after pars plana vitrectomy (PPV). Methods: This was a retrospective historical cohort study. Patients with a history of vitrectomy in one eye by a single surgeon were enrolled. IOP of the operated eye was compared to the fellow eye. Previous scleral buckling, IOP rise due to surgical/anatomic complications, silicone oil (SO) emulsification, and contralateral ocular hypertension/glaucoma at recruitment were exclusion criteria. “Significant IOP rise” (>6.0 mmHg) and development of open angle glaucoma (OAG) were the main outcome measures. Results: Two hundred and twenty‑five eyes were included. Mean and median follow‑up duration were 20.6 and 9.0 months, respectively. Mean baseline IOP and mean final IOP were 13.53 ± 3.75 mmHg and 16.52 ± 6.95 mmHg, respectively (P < 0.001). Forty‑three patients developed “significant IOP rise” with no statistically significant relation to the indication of vitrectomy, the postoperative lens status, and number of vitrectomies (P = 0.410, P = 0.900, and P = 0.160, respectively). SO injection raised the probability of IOP rise in the long‑term (P = 0.028). OAG occurred in 17 patients (7.5%) with no association to SO tamponade (P = 0.840). “Significant IOP rise” and OAG occurred in 3 and 1 control eyes, respectively, significantly lower than the rates in study eyes (P < 0.001). Conclusion: Mean IOP slightly rose in the long‑term after PPV. SO tamponade was associated with IOP rise in the long‑term but not with the incidence of OAG. Both IOP rise and OAG were more probable after vitrectomy.