Fluctuations in angle lambda with the pupil diameter and correlations with biometric values in a healthy population

The anatomical and dynamic description of the eyeball provided by physiological optics relies on several angles formed by the intersection of a number of axes. 1 Some definitions lack consensus, and variations are encountered in the literature. 2 Here, angle alpha (α) is defined as the angle formed by the optical axis (a line connecting the nodal point and the apex of the cornea) and the visual axis (shown in Figure 1 as a broken line between the fixation point and the fovea, passing through the nodal point). Angle kappa (κ) is defined as the angle between the visual