Surface topography measurement systems

A device comprising:

• an optical element having an interior including a rigid, optically transparent material;
• a first surface of the optical element, the first surface including a region with an optically transparent surface for capturing images through the optical element;
• a second surface of the optical element opposing the first surface;
• a center axis of the optical element passing through the first surface and the second surface;
• and
• a layer of pliable, optically transparent material disposed on the second surface and attached to the second surface, a first side of the layer adjacent to the second surface of the optical element having a second index of refraction matched to a first index of refraction of the second surface, and a second side of the layer opposing the second surface of the optical element having an optical coating with a predetermined reflectance, wherein the second side of the layer is configured to conform to a target surface, wherein the pliable, optically transparent material includes at least one curved optical surface.