Amoebic Keratitis

Abstract

A 67-year-old man with chronic keratitis was treated with a multitude of antibiotics, corticosteroids and other medicines. Despite temporary relief, perforation with iris prolapse occurred about 4 months after the initial symptoms, and the eye had to be removed. Histological examination revealed cystic bodies in the corneal stroma which could be identified as belonging to the genus Acanthamoeba. Trophozoites were seen as well. Although these amoebae are free-living organisms, occurring almost everywhere in the water and air, corneal infections are rare and have been reported only recently. It has been suggested that Acanthamoebae may only invade the tissues in the case of mixed infections or in corneas with a reduced immunological response, e.g. after corticosteroid therapy. Conservative therapy seems to have little effect, although antibiotic/antiviral/antimycotic treatment should supplement antiamoebic therapy, considering the possibility of mixed infections. Penetrating keratoplasty was indicated in most of the reported cases and usually had a beneficial effect.

Fungal and Parasitic Infections of the Eye

“…Hypopyon, hyphema, and uveitis may be present as well (119). Histologic examination demonstrates the presence of both trophozoites and cysts in the cornea (113,119,131,162,295). It has been postulated that the intense inflammation associated with Acanthamoeba keratitis occurs only after the death of the parasite (138).…”

Ceratite bilateral por Acanthamoeba: relato de caso

“…A Acanthamoeba pode ser encontrada na água doce, água salgada, solo e ar (31) , em quase todas as regiões do globo (32) , indicando uma maior incidência de ceratite por este parasita. Uma explicação para tal fato, seria a transformação da Acanthamoeba de uma forma saprófita inócua, em um patóge-no virulento, com a contribuição de alguns fatores, como o uso indevido de esteróides ou infecções oftalmológicas concomitantes (33) . Existe um consenso que o trauma e hipóxia no epitélio corneano induzidos pelas lentes de contato poderiam facilitar a invasão da Acanthamoeba no estroma corneano, enquanto que a anti-sepsia inadequada das lentes de contato possibilitaria contaminações bacterianas e fúngicas, produzindo um meio de cultura favorável ao crescimento da Acanthamoeba (34)(35) .…”

Bilateral <i>Acanthamoeba</i> Keratitis in a Gas-Permeable Contact Lens Wearer

“…It is reasonable to sup pose that the transformation of Acanthumoeba from an in nocuous saprophyte into a virulent pathogen may take place with the contribution of further clinical factors, as improper use of steroids or concurring ophthalmic infections [12].…”