Fig. 1.

Geometry for determining the sensitivity vector$\tilde{K}=({\widehat{K}}_i-{\widehat{K}}_o)$ when the specimen is illuminated by a spherical wavefront generated by the light source and observed at the view point. Refraction implies the bending of the light when passing from air to phosphate-buffered saline solution (PBS). Dimensions are in mm and are not to scale.