A method and apparatus is disclosed for continuously monitoring hemoglobin saturation in the blood of premature infants. A substantial portion of the eye fundus is illuminated by passing at least two frequencies of light through the pupillary opening. The light scattered from the fundus is collected as it passes out through the pupillary opening and its intensity is measured. Calculations known in the art are used to determine blood hemoglobin based on the intensity of the scattered light. A contact lens with associated fiber optic links is used to illuminate the infant eye and to collect the scattered light.