A 58-year-old man with right eye uveitic glaucoma was successfully implanted an Ahmed valve (New World Medical, Rancho Cucamonga, CA, USA) to control his intraocular pressure. Glaucoma drainage device, with increasing popularity, would show up on radiological imaging, and be mistaken as foreign body, especially with its size, superior location to the eye, and heterogeneous radiodensity throughout. The Ahmed valve appears as a signet ring on computed tomography [Fig. 1]. The difference in radiodensity of the polypropylene body from the remaining silicone part outlines its ring-shaped appearance. This is more obvious especially with 3D reconstruction [Fig. 2], making it a signature of glaucoma implant.
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