The effect of vitrectomy with silicone oil tamponade on intraocular pressure and anterior chamber morphology

We measured the tamponading effect of silicone oil, saline and air after vi trectomy, on intraocular pressure and aqueous humor outflow in 85 patients with highly proliferative retina and vitreous changes. Silicone oil as reti nal tamponading agent after vitrectomy was used in 45 patients, and saline or air in 39 patients. The mean intraocular pressure measured at one month after treatment was greatly elevated in patients with silicone oil tamponad e as compared to those with saline or air tamponade. At 6 and 12 months exa minations, mean intraocular pressures were compared in these two groups of patients. Gonioscopy revealed silicone oil emulsification and presence of e mulsified bubbles in the anterior chamber in 22.22% of patients, and narrow ing of the chamber angle in several patients with silicone oil tamponade. I ntraocular pressure elevation following vitrectomy with silicone oil tampon ade was found to be of transient rather than permanent nature, since it reg ressed after silicone oil removal. This transient elevation was due to sili cone oil tendency to emulsify. Silicone oil bubbles changed the morphology of the anterior chamber angle and fine trabecular structures by creating a barrier to aqueous humor outflow.