Bilateral traumatic expulsive aniridia after phacoemulsification.

We report a case of bilateral traumatic expulsive aniridia after uneventful phacoemulsification through small clear corneal incisions. Phacoemulsification was performed 8 and 13 months prior to the trauma in the left and right eyes, respectively. In both eyes, the intraocular lens and capsular bag were undisturbed after trauma. After resolution of hyphema, transient elevated intraocular pressure, and anterior chamber inflammation, best corrected visual acuity returned to 20/25 in each eye 6 months later. Self-sealing clear corneal wounds likely serve as a decompression valve during blunt trauma, thus preventing devastating intraocular damage and globe rupture. The intraocular lens may absorb the external force, therefore preventing damage to the capsular bag and zonules as well as preventing prolapse of posterior structures. A review of previously reported cases of traumatic aniridia is also presented.

INTRODUCTION

With advances in cataract surgery, small, self-sealing, clear corneal wounds are now the standard of practice. These wounds have been tested in cadaver eyes and proven to withstand high levels of external pressure.12 With blunt ocular trauma, these post-surgical eyes are especially prone to injury. We report a case of bilateral iris expulsion following two separate incidents of blunt trauma. Both lenses and capsular bags were left intact. Even with small sutureless corneal wounds, iris expulsion can still occur.

CASE REPORT

An 87-year-old African American female underwent uneventful phacoemulsification of her right eye followed by her left eye 3 weeks later. An acrylic one-piece intraocular lens (IOL) (SN60WF; Alcon Labs, Fort Worth, TX, USA) was placed through a 2.85-mm clear corneal incision inside the capsular bag in the right eye and a silicone three-piece IOL (LI61A0; Bausch and Lomb Inc., Rochester, NY, USA) was placed through a 3.2-mm clear corneal incision in the left eye. Postoperative best corrected visual acuity (BCVA) was 20/25 in both eyes. Eight months postoperatively, the patient fell and struck the left side of her head on concrete. She immediately noticed decreased vision and pain. Ophthalmic evaluation of the left eye was performed 1 day following the trauma, and the BCVA was 20/50 and intraocular pressure (IOP) was 34 mm Hg in the left eye. The patient had significant upper and lower eyelid edema and ecchymosis. Slit-lamp examination revealed 2+ microcystic edema and pigment and minimal loose iris tissue was present at the clear corneal incision. The incision was Seidel negative. The anterior chamber was deep and well formed with a 2.4-mm hyphema. There was no remaining loose iris tissue elsewhere. The posterior chamber IOL was intact inside the capsular bag. The posterior segment exam was unremarkable. The patient was started on topical IOP lowering medications, moxifloxacin four times daily and prednisolone acetate six times daily which were tapered over 1 month.

At the 1-month follow-up visit, the BCVA was 20/30 and IOP was 18 mm Hg in the left eye. The patient was taken to the operating room 2 months after the trauma for a revision of the phacoemulsification wound, with excision of the loose iris tissue within the wound.

The patient progressed well after revision surgery until she fell again 4 months later hitting her right periorbital area on concrete. The BCVA in the right eye on the day following trauma was 20/40 and the IOP was 19 mm Hg. On slit-lamp examination, she had a small amount of pigment at the corneal phacoemulsification wound, which was Seidel negative. The anterior chamber was well formed with a 2-mm hyphema. There was no visible remaining loose iris tissue elsewhere. The posterior segment exam was unremarkable. The patient was started on topical prednisolone acetate four times daily tapered over 1 month.

On the 6-month follow-up visit, the BCVA was 20/25 and the IOP in both eyes had remained normal. The capsular bag and IOLs remained intact in both eyes [Figure 1]. She denied glare and the need for colored contact lenses.

Figure 1

Total traumatic aniridia with the intraocular lens undisturbed in the capsular bag in the right (a) and left (b) eyes. Trauma occurred 8 and 13 months after uneventful phacoemulsification in the left and right eye, respectively

DISCUSSION

Traumatic iris expulsion through a sutureless phacoemulsification 5 mm × 3.5 mm scleral tunnel wound was first described by Navon in 1997.3 The authors proposed that the mechanism of injury involved aqueous outflow and iris plugging of the surgical wound, resulting in a pressure gradient across the tunnel sufficient to detach the iris and deliver it through the wound.3

In 2001, Ball described traumatic aniridia through a 4 mm × 2 mm clear corneal incision.4 Since these previous reports, several cases have been described of iris expulsion through a clear corneal incision following blunt trauma. Table 1 summarizes the case reports in the literature.3–13

Table 1

Summary of reported cases in the literature of traumatic aniridia after phacoemulsification3–13

It has been proposed that new foldable IOLs absorb the impact of the external force to a greater degree than rigid polymethyl methacrylate (PMMA) IOLs, thus preventing disruption of the capsule and zonules.7 It has also been postulated that the posterior structures are protected from prolapse by the presence of the posterior chamber IOL.8 Both of these mechanisms may have contributed to the absence of trauma to the capsular bag, IOL, and posterior structures.

Though cases exist in the literature of traumatic aniridia following blunt trauma to pseudophakic eyes, our case is unique in that it is the first case of bilateral iris expulsion and also through the smallest reported wound size of 2.85 mm. It is also interesting that different IOL models were used in each eye and neither sustained any damage despite trauma. The main complaint in similar cases is usually glare and photosensitivity. Management options include observation, colored contact lenses, and prosthetic iris implants.14