Corneal Endothelial Toxicity of Mitomycin C

AbstractMitomycin C is being used increasingly as an agent to prevent fibroblast invasion of a trabeculectomy site in glaucoma surgery. Because the drug is placed in direct contact with the lesion, albeit in a sponge or Gelfoam vehicle, there is a greater opportunity for penetration of the drug into the anterior chamber. The potential toxicity of mitomycin C on the isolated rabbit endothelium was assessed using the specular microscope. Corneal thickness was measured every 30 min during a 3 hr exposure to drug. Two drug sources were used, one with NaCl as an adjunct and the second with mannitol as an adjunct. Even low concentrations of drug, as low as 0.005 mg/ml, caused mild corneal swelling, although this concentration is 10-50 times greater than the measured mitomycin concentration in the aqueous humor. Swelling rates did not appear to be dose-related, whether mitomycin C with NaCl or mannitol as an adjunct was used as the source of drug. Care should be exercised with the use of mitomycin C to avoid sit...