A system for diagnostic imaging of a subject's eye, the system comprising: a light source configured to transmit light by stimulated emission of radiation; an optical scanning device configured to produce a vertical fan beam of light from the light source and linearly sweep the vertical fan beam from side to side; a first lens configured to focus light sent from the optical scanning device to create an virtual image plane that is coplanar with a subject's line of sight and is a vertical cross-sectional plane through a portion of the subject's eye; a second lens configured to focus light sent from the optical scanning device and scattered by the subject's eye to create a sharp focus plane which coincides with the virtual image plane of the subject's eye; a first measurement reflector disposed to receive at least a portion of the focused light and configured to reflect a first portion of the received light; a first camera configured and disposed to receive the first portion of the received light and configured to provide indicia of an image corresponding to the first portion of the received light; and a processor coupled to the camera and configured to analyze intensities of light in the image to determine a location of a reference point corresponding to an interface of a portion of the eye; wherein the linear sweep of the vertical fan beam from side to side by the optical scanning device traverses the vertical fan beam of light in and out along the virtual image plane of the subject's eye, characterised in that the system is configured such that light scattered only at substantially 90° relative to a path of the light entering the subject's eye is collected and analyzed. a light source configured to transmit light by stimulated emission of radiation; an optical scanning device configured to produce a vertical fan beam of light from the light source and linearly sweep the vertical fan beam from side to side; a first lens configured to focus light sent from the optical scanning device to create an virtual image plane that is coplanar with a subject's line of sight and is a vertical cross-sectional plane through a portion of the subject's eye; a second lens configured to focus light sent from the optical scanning device and scattered by the subject's eye to create a sharp focus plane which coincides with the virtual image plane of the subject's eye; a first measurement reflector disposed to receive at least a portion of the focused light and configured to reflect a first portion of the received light; a first camera configured and disposed to receive the first portion of the received light and configured to provide indicia of an image corresponding to the first portion of the received light; and a processor coupled to the camera and configured to analyze intensities of light in the image to determine a location of a reference point corresponding to an interface of a portion of the eye; wherein the linear sweep of the vertical fan beam from side to side by the optical scanning device traverses the vertical fan beam of light in and out along the virtual image plane of the subject's eye, characterised in that the system is configured such that light scattered only at substantially 90° relative to a path of the light entering the subject's eye is collected and analyzed.