An epidemic of corneal destruction caused by plasma gas sterilization

Background: Toxic endothelial cell destruction (TECD) syndrome after intraocular ophthalmic surgery is rare and can result from exposure to a variety of toxins. During January 8 to 14, 1998, 6 patients developed TECD with corneal edema associated with unreactive or dilated pupils at Hospital A. Methods: A case patient was any Hospital A patient with TECD within 24 hours after surgery during January 5 to 14, 1998 (epidemic period). A control was any hospital A ophthalmic surgery patient without TECD during the epidemic period. The medical records of hospital A ophthalmology surgery patients during the pre-epidemic (ie, September 1, 1997-January 4, 1998) and epidemic periods were reviewed. Inductively coupled plasma atomic emission spectrometry was used to detect trace inorganic elements on sterilized surgical instruments. Cannulated surgical instruments and laboratory rinsates were perfused directly to the corneal endothelium of isolated rabbit and human corneas. Corneal endothelial ultra-structure and swelling were assessed. Results: The rate of TECD at hospital A was higher during the epidemic than pre-epidemic period (6/12 vs 0/118, P<.001). The only change during the periods was the introduction, on November 5, 1997, of a new sterilization method, AbTox Plazlyte, for sterilization of ophthalmic surgery instruments. Findings from spectrometry revealed that copper and zinc residues were higher in instruments sterilized with Plazlyte than in those sterilized with ethylene oxide (median copper value, 7.64 mg/L vs 0.14 mg/L, respectively, P =.02; median zinc value, 5.90 mg/L vs 1.35 mg/L, respectively, P=.2). Corneal endothelial perfusion of Plazlyte sterilized-instrument rinsates or laboratory solution with copper and zinc produced irreversible damage, similar to toxic corneal endothelial destruction, to rabbit and human corneas. Conclusion: A new sterilization method degraded brass to copper and zinc on cannulated surgical instruments resulting in TECD of the cornea.