Case Report: Suspected Donor Transmission of Acanthamoeba Keratitis After Deep Anterior Lamellar Keratoplasty.

PURPOSE: In our report, we present a suspected case of donor-derived Acanthamoeba keratitis after deep anterior lamellar keratoplasty. To the authors' knowledge, there have been no confirmed cases of Acanthamoeba keratitis transmission through corneal transplantation. METHODS: Deep anterior lamellar keratoplasty was performed on the right eye of a 33-year-old man with severe bilateral keratoconus and an intolerance to all forms of contact lenses. The postoperative visual acuity deteriorated, while inflammation, rising ocular pressure, increasing corneal thickness, and severe eye pain began to present. Confocal imaging revealed hyperreflective cysts and trophozoite figures representative of amoebic keratitis. Despite an additional penetrating keratoplasty, antiamoeba therapy, and corneal crosslinking, the patient's condition worsened, resulting in stromal melt and corneal perforation. Emergent combined surgery of temporary keratoprosthesis, vitrectomy, lensectomy, and iridectomy was performed, along with Ahmed valve shunt placement and another penetrating keratoplasty. RESULTS: The infection was resistant to aggressive antiamoeba therapy, but after the emergent combined surgery, the graft re-epithelialized quickly and has since remained clear, with no presence of keratitis. CONCLUSIONS: Several signs led us to believe that this case was donor-derived. There was little opportunity for graft exposure to the amoeba, and deep amoebic cysts and trophozoites were present on postoperative week 1-a highly unusual time course and depth of invasion for primary amoebic infection. In addition, pathological analysis revealed cysts only within the confines of the donor tissue and none in the recipient; Acanthamoeba cysts would have been present in the recipient rim tissue if the infection originated from the patient himself.

Acanthamoeba adherence to contact lenses and removal by cleaning agents.

The quantitative adherence of a keratitis isolate of Acanthamoeba polyphaga to low- and high-water content non-ionic soft contact lenses and one type of rigid gas-permeable lens was investigated. Adherence of trophozoite and cyst forms of the organism was observed in vitro, and adherent amoebae counted by a plaque assay method following detachment. Trophozoites adhered to all lens types with adherence being statistically significantly greater to high water content soft lenses. Cyst attachment occurred only to the soft lenses but not to gas-permeable lenses, and was significantly higher for the high water content lenses. Attachment of cysts was significantly lower than that of trophozoites to each lens tested. Recommended cleaning procedures using two commercial solutions removed all adherent trophozoites and cysts from lenses. These studies demonstrate (i) that lenses may act as a vector in Acanthamoeba keratitis, particularly for high-water content lenses and trophozoite amoebae, (ii) that lens cleaning agents may prevent keratitis by removing adherent Acanthamoeba.