Abstract: Microsporidial keratitis is an infectious corneal disease caused by microsporidial infection. Its clinical manifestations are non-specific and often resemble conditions such as Thygeson's superficial punctate keratitis, viral keratitis, or fungal keratitis, leading to high rates of misdiagnosis and underdiagnosis. The disease can occur in both immunocompetent and immunocompromised individuals. Major risk factors include exposure to soil or contaminated water, pet ownership, contact lens wear, and the use of topical corticosteroids.Based on clinical features, the disease is primarily classified into two types: microsporidial keratoconjunctivitis, which tends to be self-limiting with a favorable prognosis, and microsporidial stromal keratitis, which is more refractory, often requires corneal transplantation surgery, and carries a poorer prognosis. Diagnosis relies mainly on laboratory tests such as corneal scraping stains and polymerase chain reaction (PCR). Regarding treatment, topical fluoroquinolones may be tried for microsporidial keratoconjunctivitis, while microsporidial stromal keratitis responds poorly to traditional anti-infective agents. Topical fumagillin eye drops could represent a promising new therapeutic approach. Enhancing awareness of this disease, achieving early diagnosis, and implementing appropriate treatment are crucial for improving patient outcomes.

Key words: Microsporidia, Microsporidial keratoconjunctivitis, Microsporidial stromal keratitis