OBJECTIVE To access the potential effect of vitrectomy and silicone oil tamponade on the choroid. METHODS Eighteen patients (18 eyes) who had undergone pars plana vitrectomy with 1,000-cSt silicone oil tamponade for proliferative vitreoretinopathy retinal detachment were included in this retrospective study. All patients underwent ophthalmologic examinations before treatment and 1 week and 1, 3, and 6 months after vitrectomy with silicone oil tamponade. Choroidal thickness was measured using enhanced depth imaging optical coherence tomography (Spectralis; Heidelberg Engineering) in a horizontal and vertical section beneath the fovea. RESULTS Choroidal thickness statistically significantly decreased till 3 months after pars plana vitrectomy with silicone oil tamponade: under the center of the fovea (P = 0.014) and in the temporal (P = 0.029), superior (P = 0.046), and inferior areas, determined at 1,500 μm from the center of the fovea (P = 0.030). After 6 months, the desired effect in the form of a decrease in the choroidal thickness was even more prominent, both under the center of the fovea (P < 0.001) and in the nasal (P < 0.001), temporal (P < 0.001), superior (P < 0.001), and inferior areas at 1,500 μm from the center of the fovea (P < 0.001). CONCLUSIONS Choroidal thickness is reduced in eyes receiving silicone oil intraocular tamponade. Silicone oil tamponade may have an impact on the structure and proper functioning of the choroid. The measurements of the choroidal thickness by optical coherence tomography might be a very good tool to detect early changes in choroidal thickness and impact the decision when to remove silicone oil.