What are prism glasses?

Prism is a special type of lens that shifts space and changes the way our eyes work, rather than just changing eyesight.

What are prism glasses used for?

  1. to improve the stability of how both eyes work together
    – crucial for reading and learning
  2. to re-orient posture and movement
    – potentially for torticolis and autism
  3. to help visual attention
    – may be useful for ADHD
  4. to compensate for field loss after brain injury
    – may be helpful for homonymous hemianopia

How do I know if I or my child needs prism?

The need for prism in a prescription is best determined by a specially trained Doctor of Optometry. The specialized tests involved are not typically conducted as part of a basic eye examination.

Where can I get prism glasses?

Any reputable source of eyewear can work with a laboratory that makes prism. Prism is obtained by either change the relationship of the center of a lens to the center of the eye, or by a specialized process that creates differential thinning.

What does prism glasses look like?

In higher amounts you can see that one edge of a prism is thicker than the opposite edge. This is only true in higher powers, as needed when patients see double, or during vision therapy. Otherwise it doesn’t noticeably change the appearance of the lens.

For how long I need to wear the prism glasses?
That depends on whether the prism is working as a support or as a therapeutic tool. It can be a few month to several year.

Does prism glasses have to be monitored closely?

Absolutely! In one sense, prism is like medication: Just because a little bit is good doesn’t mean more is better. The amount has to be carefully determined, and is as much an art based on the experience of the doctor as it is a science rooted in optics. Patients are typically monitored periodical depending on the individual case.

What changes should I see with the prism?

That depends on why the prism is being prescribed. When used for learning purposes we anticipate improved attention, concentration and fluency. When used for convergence problems we expect less eye strain or doubling. When used for developmental purposes we anticipate improved responses to other therapies.

Do I see the changes right away?

Prism is very individualized. Sometimes changes occur rapidly, but in other cases not for months. When prism has a beneficial effect initially, and then levels off, that may be a sign that the amount, the balance between the two eyes, or the direction of prism needs to be changed.