Silicone oil pupil block glaucoma in a pseudophakic eye

Abstract

Intravitreal silicone oil achieves an effective endotamponade in patients with complex retinal detachments. Silicone oil displacement into the anterior chamber risks glaucoma and endothelial failure. We describe a 52-year-old patient with pseudophakia with silicone oil endotamponade presenting with visual loss and intraocular pressure of 60 mm Hg. Inferior YAG iridotomy was undertaken to repatriate silicone oil to the posterior segment. Despite normal intraocular pressure, acute corneal oedema occurred postiridotomy, resolving spontaneously over 2 weeks. Pupil block glaucoma secondary to silicone oil requires a management approach based on an understanding of silicone oil fluidics. Careful selection of inferior laser iridotomy site is critical to effectively reverse pupil block. Anterior migration of silicone oil in patients with pseudophakia is rare. We offer an hypothesis to explain unanticipated transient corneal oedema following silicone oil displacement from the anterior chamber. Clinicians must discuss the possibility of transient or permanent endothelial failure preoperatively in this patient group.

Figure 1

Anterior segment photographs of patient with silicone oil pupillary-block glaucoma. (A) Circumciliary injection is present with mild chemosis and conjunctival recession from previous circumferential buckle surgery. New vessels are evident on the superior and inferior iris (white arrow). The cornea appears clear. The patient is pseudophakic; the anterior capsulorrhexis margin is demonstrated superiorly. There is a central, circular interface of silicone oil seen within the anterior chamber centered on the pupil (margin is defined by white arrowheads); note the specular light reflex on the superior iris. (B) Silicone oil (white arrowheads) is forming the central anterior chamber (white arrow). There is 360° of peripheral iridocorneal endothelial apposition with gonioscopy failing to reveal any angle structures (not shown). (C) An inferior nd:YAG laser peripheral iridotomy has been fashioned at the previous junction of silicone oil, iris and endothelium within an iris crypt (white arrow; compare with (A)). Mild iris bleeding is noted. (D) The communication has permitted anterior migration of aqueous through the inferior iridotomy, displacing the silicone oil globule superiorly (white arrowheads), opening the pupillary margin to aqueous and breaking pupillary block. Note deepening of anterior chamber due to presence of aqueous (white arrow).

Figure 2

Anterior segment photographs of patient with silicone oil pupillary-block glaucoma. (A) There is generalised corneal oedema (white arrow), although this appears to be more prominent centrally on this image. Descemet's membrane folds are present. Silicone oil configuration (white arrowheads) within the anterior chamber is similar to figure 1D, remains formed and pupil block remains broken. There is no hyphaema. (B) The cornea is clear, with 6 mm dilated pupil and large/patent inferior peripheral iridotomy (white arrow). The anterior capsulorrhexis margin and intraocular lens reflex are visible. A silicone oil globule is present superiorly (white arrowheads). Iris bleeding has settled, but new vessels persist. (C) Gonioscopy of the inferior drainage angle demonstrates angle recession (limits defined by white arrows). Emulsified silicone oil is not demonstrated in the trabecular meshwork, and no pathological new vessels are demonstrated in the drainage angle.