Hyperopia, myopia causes and corrective demonstrator

This product is for teacher to demon the cause

of hyperopia, myopia and correction, composed

by base, light source, removable water lens,

fixed water lens, removable focalizer, fixed lens

focalizer, activities retina and optical simulation

demo board. While in the process of teaching,

not only to move lens position, and moving

the focusing lens and a fixed focus lens to adjust

the focal length of the lens.