Importance of clinical signs leading to the diagnosis in a case of microbiological smear negative ocular microsporidiosis.

A 28-year-old patient presented to us with multifocal coarse raised epithelial lesions in the left eye associated with pain watering redness and blurred vision with a visual acuity of 20/40 in the left eye. The patient had been managed elsewhere with a course of topical moxifloxacin eye-drops four times a day and topical steroids (prednisolone acetate) 1% three times a day for 2 weeks without any resolution, which was stopped 2 days ago prior to presentation at our centre. Gram stain was negative for bacteria as well as microsporidial spores. 10% KOH was negative for fungal hyphae. Based on strong clinical signs of corneal microsporidiosis, in spite of the negative microbiology smear, the patient was started on voriconazole eye-drops five times a day. The lesions started resolving in 5 days and completely healed after 17 days of therapy. No relevant history pertaining to exposure of contaminated water, swimming or history of trauma could be elicited.