A method is disclosed for using a precision ultrasound scanning device to image the anterior segment of the human eye, automatically locate the scleral spur, and, using the scleral spur as a fiduciary, to automatically make measurements in front of and behind the iris. The scleral spur can be used as a fiduciary to make measurements that characterize the normal and abnormal shapes of components within this region of the anterior segment of the eye. One or more of the measurements of the iridocorneal angle and the anterior chamber depth can be related to other measurements behind the iris including the iris lens contact distance, the iris zonule distance and the trabecular ciliary process distance. Over a period of time, these measurements can change and can indicate a change, or be a precursor for a change, of intraocular pressure (IOP), and therefore can determine an earlier onset of glaucoma.