Virological diagnosis of anterior herpetic ocular disease on tear sample: A simple and non-invasive technique

Introduction: Virological diagnosis of anterior ocular herpetic disease (AOHD) is essential for the management of these often-chronic pathologies that may require long-term therapy. PCR has become the gold standard, but the type of sampling (tears, corneal scraping, aqueous tap) has not been standardized. In this study, we studied the technique of tear sampling for the diagnosis of AOHD. Materials and method: We retrospectively analyzed the medical files of patients with a positive tear sample (Schirmer strip) for herpes simplex 1 virus (HSV-1) in the Department of Ophthalmology of Paris-Saclay Bicêtre Hospital between January 2018 and December 2020. We studied the clinical and virological characteristics (viral loads) of these cases of proven AOHD. Results: Thirty-six samples (33 patients) were included: 12 epithelial keratitis, 9 stromal HSK with ulceration, 5 uveitis, 4 stromal HSK without ulceration, 3 blepharitis, 1 endothelial HSK, 1 neurotrophic keratitis, and 1 conjunctivitis. The mean viral load was 3.9 × 10⁵ copies/mL. Viral load was higher in cases of corneal ulceration (5.2 × 10⁵ ± 9.4 × 10⁵ versus 1.2 × 10² ± 1.7 × 10² copies/mL, P < 1 × 10⁻⁴). There was no significant difference between primary episodes and relapses. Conclusion: Tear sampling using Schirmer strips is a simple, non-invasive method that can be useful for the virological diagnosis of various clinical forms of AOHD.