Background: Intraocular silicone oil may migrate into the optic nerve or the cerebral ventricles, but little is known about the frequency of these events. The aim of this prospective neuroimaging study was to determine the frequency of extraocular silicone oil migration in humans operated for retinal detachment.

Methods: Nineteen patients included in this study were referred for silicone oil removal after uncomplicated retinal detachment surgery using internal silicone oil tamponade. Patients with a previous history of intraocular silicone oil, glaucoma or optic pit were excluded. After informed consent, the patients underwent magnetic resonance imaging (MRI). Fat saturation as well as short T1 inversion recovery (STIR) sequences combined with water saturation allowed silicone oil to be easily detectable.

Results: The mean delay between the silicone oil injection and the MRI procedure was 115 days. No extraocular silicone oil in the orbit, in the optic nerve or in the cerebral ventricles was found on MRI.

Conclusions: This is the first published in vivo study on the frequency of extraocular silicone oil migration after retinal detachment surgery. Special dedicated MRI sequences are able to accurately visualize intraocular silicone oil. None of the included 19 patients were detected with silicone oil migration into the visual pathways or intracranially, suggesting that its occurrence may be very rare, maybe only in patients with optic nerve head anatomical predispositions.