The potential for the noninvasive measurement of blood glucose concentration to improve the level of blood sugar control and the quality of life of diabetic patients has been recognized for nearly 3 decades. Because of the many challenges involved in directly sensing glucose in the bloodstream noninvasively, the approach of noninvasive measurement of glucose concentration in the ocular aqueous humor, which reflects blood glucose concentration, has been likewise pursued over those 3 decades. Moreover, studies of the dynamic relationship between blood glucose concentration and ocular glucose concentration in both animals and humans suggest minimal latency between variations in blood glucose and those in ocular glucose. In a review of technological approaches to such measurements, the most promising techniques appear to be laser-based, and include laser polarimetry and Raman spectroscopy. Results for techniques such as multiwavelength polarimetry and Raman spectroscopy have been quite good, and it is likely that one or both of these techniques, possibly combined with refractive index measurement, will yield a useful instrument for both clinical use and patient self-monitoring.