Ocular Microsporidiosis—Our Experience in a Tertiary Care Centre in North India

Microsporidia are obligate intracellular protozoal parasites. They are eukaryotic and spore forming. Increasing interest in this parasite as a pathogen in the ocular tissues in recent times is due to increasing awareness of microsporidia as an ocular pathogen and better methods of identification of the organism. It also can cause intestinal, sinus, pulmonary, muscular and renal diseases, in both immunocompetent and immunosuppressed patients. Ocular microsporidiosis can occur in isolation or as a part of systemic infections. In earlier published literature, ocular involvement in immunocompetent individuals was more in the form of stromal keratitis and immunocompromised individuals were seen to have keratoconjunctivitis. However, later studies show that this pattern has many variations. Occurrence in rainy season with exposure to muddy water and history of minor trauma is now a known factor. Identification by light microscopy from scrapings with KOH, Gram, Giemsa staining is possible. Growth of the organisms, however, is possible only by cell culture. Species identification is done by polymerase chain reaction and by electron microscopy. Immunofluorescent staining techniques are also available in advanced laboratories for species differentiation of microsporidia. Till date, treatment of ocular microsporidia has not been standardized and varies from simple debridement to use of various antibiotics, antiseptics antifungals and antiviral agents.