Mean path length inside nonscattering refractive objects

It was recently argued that the geometric optics mean path length of rays inside a refractive object under Lambertian illumination is independent scattering strength medium [Savo et al., Science 358, 765 (2017)]. We here show it is, in fact, different case zero scattering. uncover and explain role trapped ray trajectories creating this unexpected discontinuity from to low This allows us derive alternative analytic results for simple shapes. believe work provides fresh perspective on study objects, with possible applications in, example, by large particles or design optical systems.