Images in Clinical Medicine
Appearance of Intraocular Silicone Oil on Computed Tomography
N Engl J Med 2003; 348:1122March 20, 2003
- Article
A 60-year-old man presented with epiphora, or an abnormal overflow of tears, caused by bilateral primary acquired nasolacrimal-duct obstruction. Computed tomography (CT) of the orbits and sinuses performed as part of the preoperative workup showed a hyperdense mass in the posterior segment of the left eye. On questioning, the patient revealed a history of cytomegalovirus retinitis and retinal detachment in the left eye that had previously been treated with vitrectomy and silicone-oil tamponade. Silicone oil is hyperdense relative to the extraocular muscles but hypodense relative to orbital bone, as seen in a CT scan with the patient in the supine position (Panel A). The oil is roughly as dense as the crystalline lens. Since silicone oil is less dense than water, it can also be seen to move within the eye and float to the top, depending on the position of the patient's head. Panel B shows a CT scan obtained with the patient in the prone position. Vitrectomy and silicone-oil tamponade are commonly used to treat retinal detachments in which extended intraocular tamponade is required to prevent redetachment. The appearance of intraocular silicone oil can cause diagnostic confusion for clinicians, unless the appropriate history is obtained.
Gavin J. Stringfellow, M.B., B.S.
Prince of Wales Hospital, Sydney 2031, AustraliaIan C. Francis, F.A.S.O.P.R.S.
University of New South Wales, Sydney 2031, Australia
