Reconstruction of the crystalline lens full-geometry from OCT images acquired with off-axis viewing.

The crystalline lens of the eye is an optical structure that, together with the cornea, focuses images onto the retina. In a young and healthy eye, the lens is transparent and adjusts its shape to focus on near and distant objects (accommodation). With age, it loses this flexibility (presbyopia) and may later become opaque (cataract). Understanding the full three-dimensional geometry of the crystalline lens is essential for studying age-related lens growth and accommodation mechanism, as well as for the customized design and selection of intraocular lenses the for implantation in cataract surgery. While Optical Coherence Tomography (OCT) allows imaging of the central lens region visible through the pupil, conventional in vivo measurements cannot capture the full lens shape, particularly at the periphery, due to iris obstruction. In this study, we present a novel method to reconstruct the full three-dimensional shape of the crystalline lens by combining OCT images acquired with off-axis illumination at different angles. Using this approach, full lens reconstructions were achieved in eight subjects, and key geometrical parameters - diameter, volume, and surface area- were quantified, showing strong positive correlations with age. Comparisons with estimates derived from pupil-limited regions showed strong agreement, thereby validating these estimation methods.