Chorioretinal Imaging, Vascular Biomarkers, and Ultra-Trail: A Pilot Study

Retinal and choroidal microcirculation is a relevant biomarker of systemic vascular health and lies at the heart of eye-heart interactions. Noninvasive retinal imaging, particularly OCT angiography (OCT-A), now makes it possible to examine retinal and choroidal microvascularization in vivo and to study its relationship with systemic cardiovascular and neurovascular mechanisms. Ultra-endurance activities, such as ultra-trail races, induce significant systemic hemodynamic changes, including dehydration, variations in perfusion pressure, prolonged sympathetic activation, and redistribution of blood flow. These physiological adaptations could lead to acute and reversible changes in retinal and choroidal vascular parameters as measured by retinophotography and OCT angiography. Several studies suggest that intense physical exercise may be accompanied by significant changes in retinal and choroidal microvascular perfusion. In particular, a significant decrease in the vascular density of the superficial retinal plexus has been observed following intense exercise in a healthy population, suggesting a transient change in retinal microcirculation. Similarly, following a marathon, a decrease in the retinal vascular density index (RVDI) has been reported, likely related to exercise-induced vasoconstriction and a transient reduction in retinal blood flow. This decrease may also be exacerbated by the drop in systemic blood pressure and the relative dehydration observed after the race. More broadly, intense endurance exercise is accompanied by cardiovascular and neurohormonal adaptations, particularly through activation of the renin-angiotensin-aldosterone system, which may modulate ocular perfusion. Scott et al. demonstrated, following a 160-km ultramarathon, significant alterations in left ventricular function and a major elevation in NT-pro-BNP, indicating systemic cardiovascular stress that was markedly greater than that observed after a standard marathon. Furthermore, a mult