N-Acetylcystein (NAC) routinely use for liquefaction of tenacious bronchial secretion. Its efficiency was confirmed in a study that found NAC to be least irritant and the most stable one among several sulfhydryl agents. Because of its mucolytic and anticollagenolytic properties, NAC has been used in ophthalmology to treat corneal diseases, such as Keratoconjunctivitis sicca, filamentary keratitis, corneal mucous plaques and alkali- burned corneas. Corneal toxicity of NAC was observed after intracorneal injection. Evaluation of those effects on the cornea and the mucus was performed using light microscopy and histochemistry. Although different treatments with NAC were described, the effective dose without undue toxicity has not been established.

The effects of 3, 10 and 20% concentrations of N-Acetylcysteine on corneal wound healing in dogs were evaluated. Corneal wounds caused by traumatic accidents without any infection signs were selected for this research. Descemet’s membrane was intact in all of cases. 24 patients were divided to 3 treatments group.

The involved eye was treated topically with Acetylcysteine (3, 10 and 20% concentrations) in each of 8 cases separately. Corneal wounds were measured by fluorescein staining every day. The mean time of healing in the 3 group was significantly different from similar wounds treated without N-Acetylcystein (6.17± 1.94 days). It was 7.19 ± 0.75 days in the 20% group and 7 ± 2 days in the 10% group. The last two group were not significantly different (9.67± 3.01 days and 8.17 ± 3.60 days, respectively).

Compare the 3 different concentrations of the drug on the injured cornea reveal the healing process of the cornea and correlation between different stages of ulcers clinically. Ten present treated group has shown better healing time and less irritation on conjunctiva.