Although an otoscope is generally thought of as an instrument used for looking into a patient's ear, it can also be used to examine the eyes. Basically speaking, an otoscope features a magnifying glass and light source in a handheld device that allows doctors to view specific parts of the body. It can be used to check the eye for conditions such as strabismus, cataracts, or foreign bodies, and can also be used to examine a patient's pupil reflex and eye movements.