Microsporidia are unicellular, spore-forming organisms that were previously classified as protozoa but are now reclassified as fungi based on molecular and ultrastructural evidence. Ocular microsporidiosis was initially recognized as an opportunistic infection in immunocompromised hosts; however, over the past two decades, an increasing number of cases of microsporidial keratoconjunctivitis (MKC) have been reported in immunocompetent individuals. MKC is endemic in Southeast and South Asia and shows a strong association with exposure to soil or contaminated water, particularly during the rainy season. Clinically, MKC is characterized by multiple, coarse, punctate, raised epithelial lesions smaller than 1 mm, often mimicking adenoviral keratoconjunctivitis, herpes simplex keratitis, or Thygeson’s superficial punctate keratitis. This review integrates a representative clinical case with an extensive review of the literature to provide a comprehensive overview of the epidemiology, pathogenesis, clinical features, diagnostic modalities, management strategies, and prognosis of MKC.
Jinkwon Chung (2026) studied this question.