A unique glucose sensor to determine the glucose level in patients, for example, for use in treating or diagnosing diabetes. The patient's eye is automatically scanned using a source of radiation at one side of the patient's cornea. A sensor located at the other side of the cornea detects the radiation that passed through the cornea. The level of glucose in the bloodstream of the patient is a function of the amount of radiation detected at the other side of the cornea of the patient. The result is transmitted to a remote receiver that is coupled to a readout device to thereby provide non-invasive glucose determinations.