Inclusion Criteria:  Patients 18 years of age or older who underwent pars plana vitrectomy for the repair of rhegmatogenous retinal detachment (RRD) and received silicone oil as an intraocular tamponade.  Exclusion Criteria:  Patients will be excluded if they have a significant corneal opacity, uncontrolled intraocular pressure, a confounding macular pathology or optic nerve pathology or if silicone oil has been in the eye for longer than 6 months.