Bilateral microsporidial keratoconjunctivitis in a clinically healthy female receiving intravitreal steroid injections: Associations and potential risk factors.

Purpose: To present a unique case of bilateral microsporidial keratoconjunctivitis in a clinically healthy female receiving intravitreal steroid injections, and explore several associations and potential risk factors. Observations: A 75-year-old woman with chronic idiopathic anterior uveitis was receiving regular intravitreal steroid in both eyes for secondary cystoid macular edema. Flare-ups of iritis were usually treated with topical non-steroidal anti-inflammatory drops, but in the left eye the patient also received a few limited courses of topical corticosteroid. The patient regularly instilled topical cyclosporine 0.05% for dry eyes. She was otherwise clinically healthy but had low serum Immunoglobulin (Ig) M levels. There was no history of trauma or exposure to contamination. In her course of treatment, she developed a bilateral punctate keratitis. Corneal scrapings were diagnostic of Microsporidia. Topical voriconazole and moxifloxacin, as well as corneal debridement, were effective in resolving the infection. Conclusions and importance: We propose that the factors and associations described in this case--intravitreal steroid, topical steroid, topical cyclosporine, and IgM deficiency--contributed variably to create relative, local, immunologic suppression in our patient. Among these potential risk factors, we believe that intravitreal steroid exposure may be prominent. In aggregate, they facilitated development of her opportunistic microsporidial corneal infection. Eye care specialists should have a high index of suspicion for microsporidial keratitis, if they observe an atypical chronic punctate keratitis in patients with similar clinical associations.