Prism Eyeglasses

Fresnel prism Eyeglasses © 2019 American Academy of Ophthalmology

When Your Vision Becomes Two, Prism Eyeglasses to the Rescue



Prism Eyeglasses are not exactly like normal glasses. They do not improve the vision of an eye or even both and you cannot count on it to help you see better from afar or even up close. Prism glasses are actually used to help an individual’s eyes work well together.

There are some people whose eyes don’t focus at only one point; one eye is looking somewhere while the other one is looking elsewhere and this condition is called Strabismus or Squint. A condition like this causes double vision. This is most diagnosed by an eye doctor and is usually treated with prism glasses.


When your eyes wander

Prism glasses help bring the different points of focus of both eyes to a middle point by distorting the glasses. Through this manipulation, they eyes are brought to a focus as they are directed towards a middle ground.

The middle ground allows the errant eyes to see the same thing and sends the message to the brain that the eyes are working together. If used together with daily eye exercises, the condition may be alleviated and the patient need not wear prism glasses forever. Wandering eyes can be trained to focus with some determination and training.



Imagining a prism

The technology lies in the prism, which is able to bend light. As they are affixed in the glasses so that the eyes are able to look through them, the object you are looking at comes into focus. A prism can be defined as any physical object with its cross-section being the same along the entirety of its length.

You can try drawing any shape using only straight lines. If you close your eyes and imagine it to extend upwards, then you have just created a prism in your head. If you cannot imagine what a prism is, that is ok. As long as it can help you see better, you do not need a visual imagery.

This prism is used in eyeglasses to correct symptoms of double vision, convergence correction or positional correction.



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