National Eye Institute, National Institutes of Health
A Binocular Indirect Ophthalmoscope is worn on the practitioner's head.
An ophthalmoscope is an instrument used for examining the interior structures of the eye, especially the retina, consisting of a mirror that reflects light into the eye and a central hole through which the eye is examined. A Binocular Indirect Ophthalmoscope (BIO) is worn on an eye doctor's head in order to have the use of both hands to examine the eyes.
