to report a case of microsporidial keratitis unresponsive to medical treatment

a 41-year-old man presented with redness, photophobia, decreased vision of right eye with no history of significant trauma or contact lens use since 10 days before. Slitlamp biomicroscopy revealed central stromal edema and keratic persipitate masqurating herpetic endothelitis. The keratitis was not responsive to oral Acyclovir and topical steroid. After 2 weeks a dense stromal ring infiltration complicated the disease picture. Clinical impression was Acanthamobea keratitis at this point. Corneal smear and culture were negative. Confocal microscopy revealed tiny round hyper reflective elements lined up in a linear pattern which was in favor of mycrosporidial keratitis. Keratitis initially responded to Polyhexamethylene Biguanide 0.02% (PHMB) with diminution of ring infiltration, but corneal edema persisted and corneal vascularization pursued. Five month later multiple exacerbations of keratitis lead to increased stromal infiltration, deep vascularization, and hypopyone unresponsive to maximal medical treatment. Finally, the patient underwent penetrating keratoplasty.

Histopathologic examination of the corneal button showed small round gram positive elements, suggesting microsporidial infection. Three month postoperatively the graft is clear with no recurrence of infection.

Microsporidial keratitis can masqurate any other keratitis including herpetic endothelitis or acanthamoebel keratitis.