Microsporidial keratitis: need for increased awareness.

Since the devastation of the European silk worm industry in the 19th century, microsporidia have been recognized as important organisms. An enormous literature is available on their biology, phylogeny, classification, disease profile, diagnosis, and treatment; however, it is only recently that ophthalmologists have begun to take note of these organisms. The last two decades have seen several publications related to ocular microsporidiosis, in particular those forms affecting the cornea. Both immunocompetent and immunocompromised patients are at risk of developing corneal infections that may range from self limiting mild keratoconjunctivitis to severe stromal keratitis recalcitrant to medical treatment. Exposure to soil, muddy water, and minor trauma are possible risk factors. Although reliable prevalence data are lacking, recent studies indicate a high prevalence of microsporidial keratoconjunctivitis in the rainy season, especially in India and other countries with similar climates. For instance, a high prevalence has been documented in Singapore. We bring together the information available on ocular microsporidiosis.