Toxic anterior segment syndrome (TASS) is an acute, sterile, inflammatory reaction of the anterior segment after intraocular surgeries. We aimed to report an outbreak of TASS which occurred following pterygium surgeries.

A case series.

Four eyes of four patients developed TASS associated with formaldehyde after uneventful primary pterygium surgery with conjunctival autograft. No patients reported pain; all patients demonstrated diffuse corneal edema, epithelial defects, and anterior chamber inflammation without hypopyon, fibrin formation, and vitreous involvement on the first postoperative day. TASS diagnosis was made based on clinical findings. All patients were treated with hourly topical 1% prednisolone acetate (Pred Forte, Allergan, CA), moxifloxacin 0.5% (Vigamox, Alcon, TX), and 0.24% of hyaluronic acid (Artelac complete, Bausch & Lomb). Oral steroid (prednisolone 1 mg/kg) was added on the first week and gradually tapered over weeks. None of the affected corneas improved spontaneously. Best-corrected visual acuity ranged from 20/25000 to 20/200 in the second month after surgery. Keratoplasty was scheduled for all patients.

This is the first study to present TASS cases after pterygium surgery. Clinicians should be aware of TASS that can emerge after an extraocular surgery. In our analysis, since 2% formaldehyde was used by the operating room personnel for cleaning and sterilizing reusable ocular instruments, it was thought that formaldehyde was the most likely cause.