Introduction:The choroid is a thin brownish membrane composed of blood vessels, melanocytes and connective tissue. It is main function is to supply the outer layer of the retina with blood and nutrients. Silicone oil (SiO) is a widely used intravitreal tamponade in the repair of retinal detachment (RD) when long-term tamponade is needed. With the advancement of spectral domain optical coherence tomography (SD-OCT), in vivo images of the choroid with sufficient contrast and resolution are now available for measuring choroid thickness (CT) and visualizing choroid microstructures. Aim of the work: To assess subfoveal choroidal thickness changes following pars plana vitrectomy with silicone oil endotamponade for rhegmatogenous retinal detachment 3 months after pars plana vitrectomy and 1 month after silicon removal. Patients and methods: In our study we will include 25 patients who underwent Pars plana vitrectomy (PPV) and Silicon oil endotamponade injection and subsequent Silicon removal for rhegmatogenous RD in our Retina clinic. we measure SFCT 3 months after PPV and silicon injection and one month after silicon removal using optical coherence tomography (SD-OCT). Results: mean SFCT values of the RRD operated eyes were 270.6 ± 7.3 um 3 months after PPV and 252.2 ± 11.3 um 1 month after SiO removal. When the mean values were compared, the decrease in SFCT was statistically significant (p = <0.0001, ANOVA). Conclusion: SFCT seems to decrease after the removal of the SiO which indicates that choroidal parameters should be taken into account during or after surgery for rhegmatogenous RD.