USING SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY IMAGING TO IDENTIFY THE PRESENCE OF RETINAL SILICONE OIL EMULSIFICATION AFTER SILICONE OIL TAMPONADE

Purpose: To describe small hyperreflective areas using spectral-domain optical coherence tomography (SD-OCT) imaging in eyes that have had silicone oil tamponade. Methods: Retrospective case series of 11 eyes of 11 patients. The authors retrospectively identified patients who underwent vitrectomy and silicone oil tamponade secondary to a rhegmatogenous retinal detachment (nine patients), panuveitis with retinal necrosis (one patient), or recurrent full-thickness macular hole surgery (one patient) who had manifestations of silicone oil emulsion on SD-OCT imaging. Patients were monitored during the postoperative period by clinical examination and using SD-OCT. A model eye in which emulsified silicone oil had been injected in the anterior chamber was used to obtain anterior segment SD-OCT images for comparison. Results: The mean age of our patients was 50 years (range, 39-76 years). In eight eyes, the SD-OCT examination was carried out after silicone oil removal, and in three eyes, the SD-OCT examination was carried out with the oil in situ. Of the nine eyes treated for rhegmatogenous retinal detachment, five had a relieving retinectomy for advanced anterior proliferative vitreoretinopathy or for traumatic retinal incarceration (one eye). The eye treated for full-thickness macular hole had a vitrectomy, internal limiting membrane peel, and silicone oil injection for recurrent macular hole. Ten eyes showed hyperreflective, spherical, tiny droplets using SD-OCT imaging. These were thought to represent silicone oil droplets intraretinally or underneath epiretinal membranes, and one eye showed hyperreflective areas subretinally (retina detached). One additional patient was found to have tiny intravitreal silicone oil droplets after silicone oil removal. Similarly, the silicone oil appeared as multiple hyperreflective spherical droplets as detected by SD-OCT. Anterior segment studies of silicone oil emulsification in the experimental model revealed a similar appearance to that seen with in vivo SD-OCT imaging. Conclusion: The authors have found small hyperreflective areas intraretinally, subretinally, and underneath epiretinal membranes on SD-OCT in eyes that have had silicone oil tamponade for a variety of indications. The authors have seen a similar appearance when silicone oil emulsification is examined in vivo. The authors conclude that the hyperreflective areas are likely (but not certain) to be very small bubbles of emulsified silicone. Further studies are required to determine the incidence, clinicopathologic, and functional significance of probable silicone oil emulsification and deposition within the retinal layers.