ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN FUNGAL KERATITIS

Fungal keratitis presents a challenge, given its potential to serious complications, if not promptly diagnosed and treated. Anterior segment- optical coherence tomography (AS-OCT) imaging provid a range of characteristic patterns that could be used as an additional tool in diagnosis and management of fungal keratitis.

Department of ophthalmology, University Mohammed VI of science and health of Rabat, Morocco.

We describe the AS-OCT findings of two patients with fungal keratitis.

Case 1

A 78 year-old man with a history of diabetes melitus and vegetal trauma to his right eye, presented to the emergency room complaining of pain and blurred vision, in the right eye for two weeks. The visual acuity was counting fingers in the right eye. Slit lamp examination showed a conjunctival hyperaemia, a large central corneal ulcer, underlayed by stromal infiltrate and surrouded by diffuse corneal edema. AS-OCT of the right eye showed epithelial defect with anterior stromal hyperreflectivity. An hyperreflective plaque attached to the back of the cornea was also evident. The corneal endothelium–endothelial plaque boundary was unclear. This findings suggested fungal keratitis. We performed corneal scraping and started topical treatment. The culture test was positive for Fusarium spp..

Case 2

A 65 year-old man with a history of vegetal trauma to his left eye, presented to the emergency room complaining of pain and blurred vision in the right for three weeks. The best corrected visual acuity was 3/10 in the left eye. Biomicroscopic examination showed a conjunctival hyperaemia, a large paracentral inferior corneal ulcer, underlayed by stromal infiltrate. A corneal micro – abcess was detected at 2 o’clock without fluorescein staining. AS-OCT showed the inferior epithelial defect underlayed by an hyper-reflective stromal infiltrate and posterior masking.  The micro- abcess at 2 o’clock was like a small stromal hyper-reflective cystic space with intact epithelium. Even the reflectivity was high, the mask effect was absent. corneal scraping was positive for Aspergilus.

The observation of the corneal endothelial plaque can be difficult in slit lamp examination, because of corneal edema and stromal infiltrate. AS-OCT can detect the endothelial plaque in patients with fungal keratitis. Endothelial plaques have a typical characteristics in patients with fungal keratitis.  Indeed, fungal keratitis showes in AS-OCT an indistinct and irregular boundary among the endothelial plaque and the cornea. However, bacterial keratitis also exhibits endothelial like plaques, but endothelium-endothelium plaque boundary is clear.

AS-OCT can also detect other patterns in fungal keratitis like localized small cystic spaces within the stroma and necrotic stroma as shown in the second case.  Even the reflectivity is high of the micro-abcess, the mask effect is absent. In summary, AS-OCT imaging may provide supplementary information to clinical examination for diagnosing fungal keratitis.