NASA astronaut Chris Williams guides ESA astronaut Sophie Adenot during an eye exam

iss074e0433182 (April 3, 2026) --- NASA astronaut Chris Williams smiles for a portrait while guiding ESA (European Space Agency) astronaut Sophie Adenot as she peers into an Optical Coherence Tomography machine, a medical imaging device used for eye exams. Doctors on the ground monitored in real-time viewing her retina, lens, and cornea. Vision is critical to a mission’s success and doctors regularly check the astronauts’ eyes to counteract the potential effects of living in space.