Figure 2. Typical appearance of kidney-shaped and biconvex lenses. Panels A and B each show a single “slice” from the central region of a magnetic resonance imaging (MRI) scan: a nonkidney- shaped lens (A) and a kidney-shaped lens (B). Panels C and D show MRI3dX mesh models of the lenses from two eyes: a lens with a normal biconvex appearance (C) and a lens showing a depression the anterior surface, characteristic of kidney-shaped lenses (D). The scale bar in panel D is only an approximation since the true dimensions are altered due to the presentation in perspective.