Artifact in swept source optical coherence tomography due to silicone oil

Silicone oil (polydimethylsiloxane) is one of the most commonly used intraocular tamponade agents in ophthalmic practice.[12] Optical coherence tomography (OCT) has been used to study the vitreoretinal interface or retinal changes in these oil-filled eyes. One of the common artifacts seen in these eyes is the presence of a crescentic hyperreflective focus above the fovea which represents the interface between posterior margin of silicone oil and retinal surface.[3] However, in our case, due to approximation in the peripheral retina, silicone oil led to an artifactual displacement of the retina on the scan, although the interface focus is not seen due to lack of space between the retina and oil meniscus. Case Report We have devised a novel surgical sandwich technique in which a combination of C3F8 and silicone oil is used. This has the benefit of providing intraocular tamponade to both superior and inferior retina due to gas and silicone oil, respectively. With time, as the gas bubble recedes, the chorioretinal adhesion usually forms, i.e., by 2 weeks. This technique finds usefulness in cases with inferior retinal detachments to reduce the recurrence rates. The patient was a 69-year-old male who underwent a retinal detachment repair using sandwich technique – a combination of silicone oil (1000cs) and intraocular gas (14% C3F8). Fig. 1 at 1-month postoperative visit, color fundus photograph (a) and red free image (b) showed the presence of half-filled silicone oil superiorly (arrow) with attached retina. Horizontal swept source OCT scan (c) was without any artifact; however, vertical scan (d) showed an artifact, apparent posterior displacement of retinal layers (arrow) at the area of silicone oil. The half-filled silicone oil superiorly and the aqueous milieu inferiorly provide two mediums with different refractive indices leading to the origin of this artifact.Figure 1: Figure shows a color fundus photograph (a) and red free image (b) showing attached retina with half oil filled globe. Arrow in image (a) represents the silicone oil meniscus. Swept source optical coherence tomography horizontal scan (c) passing through disc and macula (below the silicone oil meniscus) showed retinal layers with altered foveal contour. Vertical scan (d) however showed the presence of posteriorly displaced retinal layers (arrow) in area corresponding to silicone oilConclusion Clinician should be aware of potential artifacts on OCT in silico ne oil-filled eyes Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.