Spectroscopic oximetry in the eye: a review

Introduction: Non-invasive measurement of blood oxygen saturation via spectroscopic imaging has provided insights into ocular physiology and the development of a variety of ocular conditions, including retinal vascular occlusion, diabetic retinopathy and glaucoma. Major developments since the late 90s have been enabled by advancements in imaging technology, computational image analysis, and innovative experimental methods. Areas covered: We review the theory of spectroscopic oximetry, the ocular blood vessels targeted for oximetry, the imaging systems utilised, and methods to validate oximetry measures. We detail the main physiological and clinical insights provided by ocular oximetry. Expert commentary: Oximetry has revealed physiological norms and auto-regulatory effects in the retina, choroid, episcleral, and bulbar conjunctival blood vessels. Retinal oximetry has provided insights into the development of diabetic retinopathy and glaucoma, and may enhance the evaluation and treatment of retinal vessel occlusion. Commercially available retinal oximetry systems have enabled oximetry in the clinical setting. The development of more sophisticated phantoms that resemble in vivo environments has helped validate oximetry applications. New insights into ocular physiology and disease are likely to be gleaned from future studies.