Traumatic aniridia with extensive episcleral pigmentation: a case report

Abstract

Background: Traumatic aniridia has been documented in eyes with a history of cataract extraction through a clear corneal wound. The proposed hypothesis is that the iris tissue was squeezed out from the corneal wound as it is a relative weak point. However, traumatic aniridia with extensive pigmentation of the episclera has never been reported. Case presentation: A patient, who has surgical histories of trabeculectomy and cataract surgery many years ago, presented with refractory high intraocular pressure (IOP), almost complete loss of the iris, and diffuse pigmentation of the episclera after he had suffered from a contusion injury. In addition to numerous pigment particles and cells in the anterior chamber and a well-centered intraocular lens, protruding uvea tissue with overlying conjunctiva adjacent to the site of trabeculectomy was noted. Gonioscopy showed absence of the iris with clear view of the ciliary body. Conclusions: The distinct presentation of this case indicates that the torn iris was displaced to the trapdoor instead of the clear cornea incision and was confined to the subconjunctival space. The scleral fistula serves as a less resistant point for releasing pressure compared to a healed corneal wound when the eye encounters a contusion injury. Further treatment options to lower IOP include repeated trabeculectomy, implantation of glaucoma drainage device, and endoscopic cyclophotocoagulation. Transscleral cyclophotocoagulation may be considered only after episcleral pigmentation has become less so as to avoid the risk of surface burn.