Posttraumatic aniridia following phacoemulsification

Abstract

A 76-year-old woman presented 2 hours after falling and striking her left eye. She had undergone uncomplicated phacoemulsification through a 2.75 mm corneal 3-step temporal incision (1.2 mm from the limbus) 7 years previously, with an AcrySof (Alcon Inc, Hunenberg, Switzerland) 3-piece intraocular lens (IOL) placed in the capsular bag. On examination, visual acuity was light perception, and periorbital bruising and a total hyphema were present. Corneal wound was Seidel-negative and the intraocular pressure (IOP) was 30 mm Hg. B-scan ultrasonography demonstrated vitreous hemorrhage and no retinal detachment. When the patient was managed 3 weeks later, visual acuity had improved to 20/40 and IOP was 14 mm Hg. With resolution of the hyphema and vitreous hemorrhage, total aniridia was evident, with IOL remaining well centred in the capsular bag (Fig. 1). There was, however, a temporal zonular dehiscence with peripheral lens capsule extending to the internal ostium of the corneal tunnel (Fig. 2). Gonioscopy did not reveal any iris remnants. The patient was followed for 6 months without any complications and visual acuity did not improve beyond 20/40. The IOP remained stable off treatment and her glare was improved with the use of a peripherally occlusive contact lens. Total aniridia as a result of nonpenetrating trauma in eyes following phacoemulsification has been rarely reported in the literature. The explanations concerning the underlying mechanism of such iris disappearance have been speculative and controversial. Ball et al. reported posttraumatic aniridia with preservation of IOL in situ following blunt injury to an eye that had previously undergone phacoemulsification through a clear corneal incision. The authors proposed 3 possible explanations for the missing iris: (i) the iris was completely disinserted but remained within the eye; (ii) the iris was disinserted and expulsed through a new traumatic wound; or (iii) the iris was disinserted and expulsed through the original cataract section. Posttraumatic aniridia following phacoemulsification was first described with a scleral tunnel incision. Navon postulated an aqueous leak created by distortion of the cataract wound (due to the blunt injury), with subsequent aqueous outflow creating a lifting force over the iris to plug the wound. The created block in aqueous flow would lead (via significant pressure elevation) to sudden iris disinsertion and expulsion through the wound. Ball et al. suggested that a smaller incision, compared with extracapsular cataract extraction, may act as a release valve during severe blunt trauma, avoiding globe rupture but inducing a complete iris avulsion rather than partial iridodialysis. Recently, Parmeggiani et al. implicated the possibility of Fig. 1—Resolution of the hyphema and vitreous hemorrhage 1 month after the blunt trauma shows total aniridia, with the intraocular lens remaining well centred in the capsular bag.