SUMMARY

The authors report the first three cases of Acanthamoeba keratitis in Rio Grande do Sul State, Brazil. All three patients were rigid gaspermeable lenses wearers, using tap water for lens cleaning. One patient had a progressive improvement in keratitis over 4 months of intensive treatment with biguanide, neomycine, metronidazole and dexamethasone drops. Therapeutic penetrating keratoplasty was necessary in the other two patients, because of failure of intensive Clinical treatment with biguanide, neomycine, propamidine and dexamethasone drops. Corneal transplantation was performed after 2 months of intensive Clinical treatment in one of these patients, and after 14 months in the other one. There was no reccurrences of Acanthamoeba keratitis during the follow-up period (16,5 and 22 months). Diagnosis was made by direct observation of cysts and trophozaites in smear from corneal scrapings in two patients and in histology from corneal buttons in the operated patients.

Key words:
Acanthamoeba sp; heratitis