Stromal microsporidial keratitis successfully treated with medical therapy



To report a case of severe stromal microsporidal keratitis successfully treated with oral albendazole and topical voriconazole.


A 71-year-old man presented with progressive vision loss and corneal opacification for one year. Initial visual acuity was counting fingers attributed to a dense subepithelial opacification. Confocal microscopy and subsequent corneal biopsy lead to the diagnosis of microsporidial keratitis. The patient completed a four-week course of oral albendazole and topical voriconazole which resulted in resolution of the corneal opacification and improvement in visual acuity to 20/250.

Conclusions and Importance

A four-week course of oral albendazole and topical voriconazole was an effective treatment for severe stromal microsporidial keratitis.


Microsporidia are a group of spore-forming fungi that rarely cause infectious keratitis. While the cornea is the most common site of ocular infection, scleritis and endophthalmitis have been described. Clinically, microsporidial keratitis is suspected when culture-negative keratitis does not respond to conventional antibiotic therapy. Methods used to diagnose microsporidial keratitis include microscopic examination of biopsy or scraping with stains such as acid fast, Giemsa, calcofluor white, or potassium hydroxide. ,

Superficial punctate keratitis secondary to microsporidia can be managed with topical agents or epithelial debridement. Definitive treatment of microsporidial stromal keratitis, however, often requires corneal transplantation. , There are several reports of successful medical treatment of microsporidial stromal keratitis. , We report a case of microsporidial stromal keratitis documented by confocal microscopy and its successful treatment with a combination of oral albendazole and topical voriconazole.

Case report

A 71-year-old man with a past medical history of coronary artery disease, diabetes, and hypertension was referred for management of progressive opacification of the left cornea. There was no history of ocular trauma or contact lens use. He had been treated at various times for over a year with topical antibacterial, antiviral, and corticosteroid regimens, as well as an oral antiviral medication without improvement. At presentation, his vision in the affected eye was counting fingers. No corneal epithelial defects were present. A dense granular opacification of the anterior stroma involved the visual axis ( Fig. 1 A). Confocal microscopy showed numerous minute oval bodies in the anterior stroma ( Fig. 2 A). A corneal biopsy revealed myriad translucent oval microorganisms in the stroma without inflammation. The majority of microorganisms were Gram-positive, periodic acid-Schiff negative, and Giemsa stain variable ( Fig. 2 B and C). The patient was started on topical vorizonazole every 2 hours and oral aldendazole 400 mg twice daily.

Fig. 1

Initial slit-lamp photograph showing stromal opacity affecting mostly temporal quadrants of the cornea and involving the visual axis (A). Resolution of stromal infiltrates and opacities after treatment. The healed area of biopsy is noted by arrows. A cataract has formed that limited his visual acuity (B).

Jan 3, 2022 | Posted by in OPHTHALMOLOGY | Comments Off on Stromal microsporidial keratitis successfully treated with medical therapy

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