Abstract:
The human eye mainly relies on the ciliary muscle to control the curvature of the crystalline lens to realize zoom. Existing demonstrations of the imaging and adjustment functions of the human eye have the limitation of failing to accurately reflect the process. In order to simulate the crystalline lens, 3D printing technology is utilized to design a variable curvature soft lens using transparent soft silicone material, and an adjustable clamping ring was used to change the curvature of the soft lens, thereby changing the focal length of the soft lens and forming different imaging effects. When the object distance is changed, the shape of the soft lens can be adjusted to make the image clear again under the condition of unchanged image distance. The experimental setup demonstrates the knowledge of the imaging and adjustment of the human eye, which can help students to recognize the zoom mode of the human eye correctly. 

Key words: human eye, crystalline lens, zoom, 3D printing, demonstration experiment