Diagnostic Tests Corneal Topography An examination technique that allows us to analyze the physical features and shape of the anterior surface of the cornea. Retinal Scanning Lasers A procedure that uses low-energy laser to image the structure of the retinal layers and optic nerve. External Ocular Photography A non-invasive procedure in which photographs are used to document conditions of the external structures of the eye. Specular Microscopy A special photographic technique that is used to evaluate the structure and function of the corneal endothelium. Refraction A test that determines the optical power of the eye and measures the combined function of the retina, optic nerve and visual pathways in the brain. Visual Field Examination A test that measures the combined function of the retina, optic nerve and visual pathways in the brain.