Acanthamoeba sclerokeratitis. Determining diagnostic criteria
M. J. Mannis, R. Tamaru, A. M. Roth, M. Burns and C. Thirkill
Acanthamoeba infection of the cornea is an entity now recognized with
increasing frequency. We saw two cases of Acanthamoeba sclerokeratitis in
contact lens wearers in whom scleritis (anterior and posterior) played a
central role in the clinical course of the disease. Scleritis is probably a
more common component of Acanthamoeba infection than has generally been
acknowledged. Posterior scleritis has not, to our knowledge, been reported
previously in this disorder. The clinical diagnosis of Acanthamoeba
infection has often been missed due to lack of a definition of the
historical and clinical criteria by which this disease is characterized. We
reviewed the 26 previously reported cases and suggest a set of criteria
that can be used to establish an early diagnosis. Historical criteria
include minor corneal trauma, exposure to soil or standing water, or
contact lens wear. Clinical characteristics include severe pain,
infiltrative (often ring-shaped) stromal keratitis, variable anterior
uveitis, epithelial erosion, scleritis, standard bacterial culture
negativity, chronicity, and lack of response to antimicrobial agents.
