It is like a kind of instrument. For the purpose of practical and convenient, it is simplified to be a glasses. Prism eye glasses' lens is made by complex synthesis technologies and special processing technologies, especially when the prism plane according to visual physiology, in order to reduce optical aberration, it is changed into a Physical therapy glasses with Complex surface just like double focus. so it is no longer a simple glass lens.
As we know, the prisms are main used for positional correction, double vision or convergence correction. The prism in the eyeglasses can bend light. It is like to a triangle or cone, the prim lenses can pull objects into focus so that the eyes can look through it since the button of the prism is on the outside of the glasses. With it, the object visualized is pulled together in both lenses to a closer point so that you can see it clear.
As we all know a prism is a solid object that has the same cross-section along the entire length of its shape. They are designed to be used when an individual is having trouble keeping his eyes working together, instead of helping a person see better at a distance or close up. And by the way of refracting or bending white light, prism eyeglasses take effect. The colors coming from a glass prism will always be in the same order, because they always refract the same way. The objects are pulled into focus, creating a clearer picture through the prisms.