Purpose <p>To characterize the in vivo morphologic and biometric changes in the lens during accommodation as a function of age by use of swept-source OCT technology</p> Study design <p>Observational, prospective study</p> Methods <p>Complete optometric and ophthalmologic examinations were performed on all the patients to determine their eligibility for inclusion in the study. The examinations included anterior segment measurements obtained using swept-source OCT. Morphologic parameters of the lens were analysed under accommodative stimuli of 0, −1, −2, −3, and −6 D. A second measurement was taken 10 minutes after the first.</p> Results <p>Three hundred eyes of 300 patients were enrolled in the study. Structural changes in the lens were observed, specifically in the anterior and posterior radii, which decreased with accommodation, and the total thickness of the lens, which increased. In patients aged younger than 40&#xa0;years, significant changes were found in the curvature radius and lens thickness during accommodation. In patients aged older than 40 years, these changes began to diminish. Significant differences between stimuli (<i>P</i> &lt;.05) were observed in all the groups, demonstrating lens variation during accommodation and its dependence on age. Repeatability analysis showed an intraclass correlation coefficient of &gt;0.700 for all the parameters.</p> Conclusions <p>During accommodation, the anterior and posterior curvatures of the lens decrease, while its thickness increases. Age-related differences remained significant, indicating persistent changes over time. Swept-source OCT demonstrated high repeatability, particularly for anterior curvature, thickness, and tilt, even under accommodation.</p>