Risk factors for the development of transient hypotony after silicone oil removal

Purpose: The purpose of the study was to determine the incidence, duration, and risk factors for postoperative transient hypotony after pars plana silicone oil removal. Methods: This was a retrospective, noncomparative, interventional case series. The records of 89 eyes of 89 patients who underwent pars plana silicone oil removal with at least 6 months of follow-up were reviewed. Postoperative transient hypotony was defined as an intraocular pressure of <6 mmHg occurring within 1 week of surgery, which recovered within 4 months after surgery. Results: Transient hypotony occurred in 35 of 89 eyes (39.3%). Thirty-three eyes recovered within 1 week after surgery. The logistic regression model, including age, number of previous pars plana vitrectomies, number of intraoperative endolaser applications, extent of remaining posterior proliferative vitreoretinopathy and the degree of proliferative vitreoretinopathy removal, number of preoperative antiglaucoma ophthalmic solutions, duration of postoperative anterior chamber inflammation, axial length, preoperative intraocular pressure, and duration of oil tamponade, showed that only axial length was significantly associated with the development of postoperative transient hypotony (odds ratio = 1.385, P = 0.023). Conclusion: Transient hypotony frequently developed after silicone oil removal, and most cases recovered within 1 week postoperatively. Patients with a long axial length had increased odds of developing transient hypotony after silicone oil removal.