Non-invasive biomarkers of perioperative stress in ophthalmic surgeons: Heart rate variability, cortisol and salivary copeptin in a feasibility study - Rubén Cabrera Beyrouti; Marina López-García; María Eugenia Torregrosa Quesada; Jorge Francés Ferre; Ezequiel Campos-Mollo; Rocío Alfayate Guerra; Adolfo Aracil-Marco (PLoS ONE, 2026)