Monkeypox-related ophthalmic disease (MPXROD): Monitoring the antiviral effect of tecovirimat with monkeypox virus detection in tear samples.

Introduction: Although monkeypox-related ophthalmic disease (MPXROD) is rare, visual impairing complications have been reported. At present, tecovirimat is the standard-of-care antiviral treatment. In this MPXROD case, the effect of tecovirimat was assessed with PCR analysis of tear samples and concurrent monitoring of inflammation with laser flare photometry (LFP).

Case description: The patient presented with a palpebral lesion and a corneal ulcer in his right eye, with complete absence of the corneal epithelium, high intraocular pressure and anterior uveitis. MPXV-DNA was detected in tear samples with real-time PCR (RT-PCR). A total volume of 0.5 ml tear-wash was aspirated from the inferior fornix, following instillation of saline onto the ocular surface. In addition, LFP was used to quantify inflammation in both eyes. Viral load in tear samples was detected prior to treatment initiation. In the left eye, tear samples tested negative for MPXV-DNA one week post-treatment while MPXV-DNA was still detected in the right eye, before reaching undetectable levels four weeks post-treatment. Objective quantification of anterior chamber inflammation through LFP demonstrated gradual decrease that was more pronounced in the affected right eye and coincided with the clinical improvement of the corneal ulcer.

Conclusions: This case of Mpox related corneal ulcer with associated uveitis manifests the feasibility of monitoring the antiviral effect of tecovirimat with virus detection in tear samples and LFP. Our observations indicate that tecovirimat resulted in viral load reduction in both eyes. RT-PCR MPXV detection in tear samples and LFP represent noninvasive tools that could assist with treatment response monitoring.