Eyeball instrument is a demonstrator for primary school's nature, junior high school's physiology and health, senior high school's and university's biology teaching. It is equipped with a variable curvature lens, but it can not be used to explain the structure of the eyeball, and can also demonstrate the formation of vision, the principle of near and far vision and the method of correction. In physics textbooks, optical imaging is often explained by ophthalmoscope, which is also an indispensable instrument in physics. Therefore, it is an interdisciplinary instrument with large coverage.