Role of Anterior Segment Optical Coherence Tomography in Monitoring Epidemic Keratoconjunctivitis

Purpose: To describe, through anterior segment optical coherence tomography (AS‑OCT) images, the different phases of epidemic keratoconjunctivitis (EKC) and show the impact of topical steroid on the course of this disease. Methods: A prospective observational study included 38 eyes (28 patients) with a presumed EKC complicated by subepithelial infiltrates (SEIs) and treated with topical fluorometholone. Slit‑lamp examinations and serial AS‑OCT were performed on days 7, 14, 30, 90, 180, and 210. The thickness of the whole cornea and thickness of the corneal epithelium were measured with AS‑OCT and correlated to the clinical findings on slit‑lamp examination in the different EKC phases. Results: In all patients, on day 7, the AS‑OCT showed hyperreflective dots that were limited to the epithelial layers of the cornea and slightly rising above the epithelial surface, corresponding to the confluence of the punctuations of punctate epithelial keratitis. On day 14, a hyperreflective line in the Bowman’s layer with intact epithelium was noted. On day 30, this hyperreflective band extended rapidly toward the anterior stroma, becoming thicker and more intense, corresponding to the SEI. They gradually decreased in number, intensity, and extent following treatment by topical steroids in 71.4% of the cases. Only two patients had persistent SEI. They were refractory to 3‑month treatment by steroids. In these patients, who had persistent SEI, AS‑OCT showed that the hyperreflective areas became well‑defined, plaque‑like lesions with sharp margins associated with disruption of Bowman’s layer, localized epithelial thickening, stromal thinning, and a decrease in pachymetry. Conclusion: AS‑OCT can be a valuable tool that provides a range of characteristic patterns of EKC and helps in monitoring it.