Digital imaging,spectroscopy, and liquid crystals in a hand‐held,non‐invasive device to determine hemoglobin concentration

Abstract— Anemia is a significant public‐health concern both in the United States and throughout the world. This disorder of low hemoglobin concentration in the blood, which often lurks undetected for long periods, contributes significantly to mortality and morbidity and is a major cause of lost revenues from workforce shortfalls, particularly in developing countries where the incidence of anemia is higher due to malnutrition and parasitic disease. The gold standard for measuring hemoglobin is a blood test requiring phlebotomy and laboratory quantification. Current physical examination techniques and non‐invasive adjuncts for detecting anemia are not sensitive and are subject to user variability. There is an urgent need for a hand‐held device which can measure hemoglobin concentration accurately, inexpensively, and non‐invasively. The evolution of a device from its early inception, which analyzed color decomposition in a digital image of the eyelid, to its final version that is a light, inexpensive, hand‐held, non‐invasive device utilizing liquid crystals to delineate the spectroscopic characteristics of the reflected light from the palpebral conjunctiva (the inside of the lower eyelid which contains many small blood vessels) and determine hemoglobin concentration in the circulating blood will be discussed. The future refinements required for bringing such a device to the market will also be discussed.