Description

A 27-year-old immunocompetent woman presented to our clinic with redness, mild pain and blurring of vision in her left eye (LE) for 3 weeks with no preceding history of injury or contact lens wear. At presentation, her visual acuity was 20/20 and 20/60 in the right eye and LE, respectively. Slit lamp examination of the LE revealed multiple, small (0.1–0.5 mm) raised, coarse round-oval epithelial lesions which stained variably with fluorescein (figure 1A). Anterior segment optical coherence tomography (AS-OCT) showed hyper-reflectivity in these areas of punctuate epithelial keratitis with normal reflectivity of the underlying stroma and endothelium (figure 1B). The diagnostic scraping revealed microsporidia spores (figure 2A,B). All visible lesions were debrided gently, and topical moxifloxacin 0.5% (Vigamox, Alcon) was prescribed four times a day. Although PCR could not be performed, the species of microsporidia was most likely Vittaforma corneae in accordance with previous literature published from our population.1

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Figure 1

(A) Slit lamp photograph at presentation shows multiple, coarse, round-oval raised epithelial lesions. (B) AS-OCT shows hyper-reflectivity in the area of infiltration. (C) Slit lamp photograph showing DM folds, large KPs confined to and more prominent centrally and inferiorly. (D) AS-OCT shows increased corneal thickness, with elliptical hyper-reflective areas on the endothelium corresponding to the KPs. (E) Slit lamp image shows peripheral nummular lesions with resolved KPs. (F) AS-OCT shows resolution of corneal oedema and KPs. AS-OCT, anterior segment optical coherence tomography; DM, Descemet membrane; KP, keratic precipitate.

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Figure 2

(A) Gram staining of the corneal scraping showing multiple oval, non-budding Gram-positive microsporidial spores (magnification ×1000). (B) Fluorescence microscopy of calcofluor white stain showing numerous, small, oval spores of microsporidia (magnification ×400).

She presented 12 days later with a drastic drop in vision to 20/400 in her LE. Examination showed unexpected presence of stromal oedema and Descemet membrane folds, with diffuse large pigmented keratic precipitates (KPs) (figure 1C). Anterior chamber revealed 2+ cells. AS-OCT showed pachymetry of 704 microns (due to oedema) and elliptical hyper-reflective projections (figure 1D) on the endothelium corresponding to KPs.

Diagnostic aqueous tap was done and subjected to PCR test for microsporidia, herpes simplex virus (HSV), cytomegalovirus and varicella zoster virus DNA, which was negative for all. Tablet Acyclovir 400 mg five times a day and prednisolone acetate 1% eye drops every second hour were started. There was rapid improvement in the condition and topical steroids were gradually tapered. At 1 month, the endotheliitis had completely resolved. The corneal periphery revealed nummular subepithelial scars with a visual acuity of 20/20 at the 3-month follow-up visit. (figure 1E,F).

Keratoconjunctivitis and stromal keratitis as a spectrum in ocular microsporidiosis has been well reported.2 3 Anterior uveitis in the epithelial variant is infrequent, occurring in 1.0%–19.4% of the cases reported in large case studies.4 5 Our case showed a very dramatic anterior segment inflammation with corneal oedema and large, pigmented KPs and drop in visual acuity following the initial presentation. This could have been due to immune-mediated endotheliitis or due to a new or reactivated HSV infection. We performed aqueous tap to rule out possible active microsporidial infection and viral aetiology. However, since the diagnostic PCR was negative for the viral panel and there was marked improvement in the clinical picture more likely due to the use of topical steroids than the antivirals, we hypothesise that this is a rare occurrence of immune-mediated endotheliitis following epithelial keratoconjunctivitis due to microsporidia, which resolved with sequelae of corneal scarring.