Retinal toxicity of intravitreal ethyldeoxyuridine and zinc.

We investigated the toxicity of intravitreal zinc sulfate, zinc gluconate, and ethyldeoxyuridine (EDU) in albino rabbits. Various concentrations of EDU were added to the infusion solution during pars plana vitrectomy. Retinal changes were observed by light microscopy after intravitreal injections containing 20 micrograms of zinc gluconate, all concentrations of zinc sulfate, and 400 micrograms of EDU. No histologic or electroretinographic alterations occurred with doses of 15 micrograms or less of zinc gluconate or 200 micrograms or less of EDU. When added to the vitrectomy solution, concentrations of 20 micrograms/mL or less of EDU appeared nontoxic to the rabbit retina.