Trachipleistophora hominis: molecular characterization of a rare pathogen causing microsporidial stromal keratitis.

The authors report the clinical and microbiological findings of a unique case of stromal keratitis caused by a rare microsporidium, Trachipleistophora hominis. This case of stromal keratitis was in a 49-year-old male with a history of COVID-19 infection and diabetes mellitus. Corneal scraping specimens revealed numerous microsporidia spores upon microscopic examination. PCR of the corneal button revealed the presence of T. hominis infection, which could be controlled by penetrating keratoplasty surgery. The graft was clear with no recurrence of infection until the last follow-up 6 weeks postsurgery. This is the first case of human stromal keratitis caused by this organism in a post-COVID infection, confirmed by molecular diagnosis.

Femtosecond laser-assisted anterior lamellar keratoplasty in stromal keratitis caused by an Endoreticulatus-like microsporidia.

PURPOSE: To describe a case of stromal keratitis caused by an Endoreticulatus-like microsporidia satisfactorily treated with femtosecond-assisted anterior lamellar keratoplasty (femto-ALK). METHODS: Case report. RESULTS: A 65-year-old healthy woman had a 10-month history of foreign body sensation and blurred vision after a flying insect struck her right eye. The patient presented with focal central to paracentral anterior stromal infiltration and edema with keratic precipitates of the right cornea. Confocal microscopy showed enhanced keratocytes with intracellular hyperreflective round and ovoid bodies confined to the anterior two thirds of corneal stroma. Femto-ALK was performed for excisional biopsy and replacement with anterior stromal donor cornea. A modified trichrome stain of corneal tissue showed numerous microsporidial spores whose small subunit rRNA sequence belonged to that of an Endoreticulatus-like microsporidia. CONCLUSIONS: Besides systemic infection, Endoreticulatus-like microsporidia can cause stromal keratitis. With careful patient selection, femto-ALK may be considered a new surgical alternative with satisfactory treatment outcomes.

Deep anterior lamellar keratoplasty to treat microsporidial stromal keratitis.

PURPOSE: To describe deep anterior lamellar keratoplasty (DALK) as a surgical option to treat a case of severe microsporidial stromal keratitis in an immunocompetent patient. MATERIALS AND METHODS: This study is a descriptive case report. A 42 year-old Pakistani woman had an 8-year history of symptoms in the left eye. She had been previously provisionally diagnosed as suspected herpes simplex keratitis or Thygeson keratitis. At presentation, her best-corrected visual acuity was 20/20 OD and 20/200 OS. Examination of the left cornea revealed irregular, central, deep stromal opacification with keratitic precipitates and occasional cells in the anterior chamber. Investigations for mycobacteria, syphilis, and a tetraplex test were normal; all other hematological/biochemistry/virology investigations were normal-she was not found to be immunocompromised. RESULTS: A corneal biopsy confirmed microsporidial infiltration of the stroma. After intensive medical treatment with topical fumagillin and oral albendazole without resolution, DALK was performed with total stromal replacement using the big-bubble technique. One year postoperatively, the graft remained clear with no evidence of recurrence and best-corrected visual acuity was 20/40 OS. CONCLUSIONS: Microsporidial stromal keratitis is rare. Conventional surgical treatment for such a condition has been penetrating keratoplasty. DALK may be considered an option for visual rehabilitation in these cases.