Persistent Intraocular Pressure Elevation after Silicon Oil Removal in Patients with Post-Pars Plana Vitrectomy

Background: It is well-known that silicon oil (SO) injection into the vitreous cavity after pars plana vitrectomy is usually associated with high intraocular pressure. Objectives: To determine the influence of silicon oil (SO) removal on IOP level after pars plana vitrectomy for spontaneous rhegmatogenous retinal detachment (RRD) Subjects and Methods: A prospective study was conducted at Ibn Al-Haitham eye teaching hospital, Baghdad- Iraq. Intraocular pressure (IOP) was measured pre and post SO removal in patients who have underwent retinal detachment surgery with SO injection of 1000 centistokes (cSt) viscosity. Baseline IOP was measured for all the patient before the SO removal. Follow-up was performed at 1, 4, and 8 weeks after SO removal. IOP was measured by Goldman applanation tonometer. Patients with IOP > 21 mm Hg at 8 weeks post-operatively with or without anti-glaucoma mediations were considered as persistent IOP elevation after SO removal. Result: Sixty eyes of 60 patients were included. Twenty eyes had persistent IOP elevation after SO removal on first week postoperative. It decreased to 14 eyes on 4th week after SO removal and further decreased to 12 eyes on 8th week af-ter SO removal. The percentage of persistent IOP elevation following SO remov-al was about 20%  on 8th week of SO removal.  Conclusion: Persistent IOP elevation sometimes happens after SO removal. Therefore, removing SO does not simply treat the elevated IOP happened during SO injection. Patients after SO removal should be followed up for IOP for several weeks and should be treated medically or surgically as required.