Technology to determine the angle of repose of a lens, such as the angle of repose of a contact lens on an eye, includes storing an image including the lens captured using a camera and executing graphical user interface logic. The graphical user interface logic includes a frame or frames including the captured image, and graphical constructs prompting input identifying a set of locations on the captured image that are usable to define a location of the lens in the image, and a location usable to define an angle of repose of the lens in the image. The input data accepted via the graphical user interface is processed to determine angle of repose of the lens. The angle of repose of the lens is used to produce a specification for a lens.
