What Are Prisms In Eyeglasses and How Can They Help Me?

eye brain graphical banner

Most people’s idea of a prism is the well-known picture of a beam of light entering one side of a triangular piece of glass and being spit up into the rainbow of colors on the other. That is a prismatic effect that glass or plastic has on light.

Prisms that are prescribed in eyeglass lenses are quite different and can have profound effects on the brain.

A prism has a base and an apex just like a triangle. Light that comes into a prism is always turned in the direction of the apex.

There are two types of prisms: compensatory and yolked. A compensatory prism is one that “compensates” for a deficiency or weakness in your brain’s ability to fuse together the separate images from your right and left eye.

When this weakness exists, you would have blurry or double vision and you would need to apply a lot of effort to produce one single image of the world you view.

Our ability to see single should be effortless so that you can have the required energy to pay attention to your environment and react appropriately to it. When you use a great deal of subconscious energy to maintain single vision, many symptoms can occur.

A few of the symptoms are:


-Double vision when tired

-Lack of focus

-Words moving on a page

-A dislike of reading

-Fatigue whenever doing a visual task for a prolonged period of time

Properly prescribed prisms can alleviate these symptoms. Although all eye doctors are trained in the use of compensatory prisms, less than 30% of them routinely do the tests to determine their usefulness in relieving symptoms.

The other type of prism is a yolked prism. These prisms have the base of the prism on the same side in each eye glass lens to work together (“yolked”) as opposed to compensatory prisms which are on opposite sides.

Yolked prisms are more about moving space and your body’s posture as opposed to compensatory prisms which move the perception of objects. 

How you perceive space is a function of your brain’s interpretation of the visual signals coming into it.  This is critical in your ability to accurately navigate your world. When your brain misinterprets space there a number of symptoms that can occur, some are:

  • -Headaches
  • -Clumsiness
  • -Motion sensitivity
  • -Motion sickness
  • -“Drifting” while walking straight ahead
  • -Poor attention to detail visually and in hearing

Additionally, yolked prisms can be used to stimulate certain areas of your retina which have direct connections to different parts of your brain. For instance, stimulation of the bottom part of your retina with a base down yolked prism, will send more signals to the temporal lobe.

The temporal lobe is the place in your brain where short term memory resides. Language comprehension and speech reside here as well as emotions. There are many strategies to help the temporal lobe and sending additional retinal signals to it is one of them.

Finally, when you move space with yolked prisms you stimulate a part of the brainstem that causes your body’s posture to change.

If you want more information about how prisms in glasses can help your brain work more efficiently and reduce or eliminate some of the symptoms mentioned above, please call Eye Brain Connection at 303-838-9355 or visit our website, EyeBrainConnection.com and request a free thirty minute consultation.

What Are Prisms In Eyeglasses and How Can They Help Me?
Scroll to top