Clinical characteristics, progression patterns and treatment outcomes in microsporidial keratoconjunctivitis: a prospective study in Thailand

Abstract

Purpose: To assess the clinical characteristics, progression patterns, and treatment outcomes of microbiologically confirmed microsporidial keratoconjunctivitis (MKC).

Methods: This prospective cross-sectional study included patients with superficial punctate epithelial keratitis clinically suspected of MKC. Comprehensive slit-lamp examinations were conducted, and corneal scraping was performed for Gram-chromotrope staining and polymerase chain reaction (PCR) analysis. A standardized questionnaire gathered demographic data, clinical features, and risk behaviors. Treatment regimens and corneal findings, including medication and frequency, were documented at each visit.

Results: PCR confirmed the diagnosis of MKC in 96 out of 117 eyes (82.1%), identifying Vittaforma corneae in 93.7% of cases, Microsporidium sp. in 4.2%, and Encephalitozoon hellem in 2.1%. All cases exhibited similar characteristics and pattern of progression, including elevated epithelial lesions in diffused distribution (34.1%), typical target lesions (31.3%), and subepithelial infiltrations (41.7%). Treatment with topical moxifloxacin, with or without oral albendazole, followed by topical steroids for subepithelial infiltrates, led to clinical improvement within approximately two weeks, with 52% of patients achieving complete recovery.

Conclusions: This study identifies key clinical features and progression patterns in MKC. Topical fluoroquinolone monotherapy, or its combination with topical steroids or oral albendazole, results in favorable visual outcomes without corneal scarring. These insights may inform and enhance clinical management of MKC.

Keywords: Microsporidia; Microsporidial keratitis; Microsporidiosis; Superficial punctate keratitis.