This invention is a wearable ring of optical biometric sensors comprising an arcuate array of light emitters and light receivers which is configured to collectively span at least half of the circumference of a person's wrist, finger, or arm. Light energy from the light emitters which has passed through the person's body tissue and/or has been reflected from the person's body tissue is analyzed in order to measure biometric parameters such as the person's oxygenation level, hydration level, glucose level, pulse rate, heart rate variability, and/or blood pressure.
