Optical coherence tomography (OCT) scan data of a subject is acquired over a region of interest which can include an optic disc or a macula of a retina. Layer boundaries of retinal layers are identified in the OCT scan data to facilitate measurements. In one aspect, a measurement related to ratio value between a total backscattered signal intensity of one or more target layers of the retina and a total backscattered signal intensity of one or more reference layers is computed on a location-by-location basis within a region of interest of the OCT scan data. Measurements can be collected, aggregated, analyzed, and displayed in connection with other information taken or derived from the OCT scan data.
