• FREE SHIPPING
    • - Fast Domestic & International Delivery*
    • - Secure Service with Leading Delivery Companies
    • - Free Shipping on all orders over $29
    • More Info >
  • 100 DAY RETURNS
    • - Full Refund & Exchanges Within 100 Days
    • - 2 Year Warranty on ALL Sunglasses & Eyeglasses
    • - 2 Year Warranty on ALL Prescription Eyewear
    • - 3 Month Warranty on ALL Contact Lenses
    • More Info >
  • BEST PRICE GUARANTEE
  • FREE LENSES
    • We offer free basic 1.5 index lenses on all prescription eyeglasses. We provide opportunities to upgrade and add features during checkout. We make shopping online for your glasses simple, efficient and safe.
  • VISION CARE
TOLL FREE 833-666-0288
  • - Available Mon - Fri, from 9am - 6pm EST
Eyeglasses | Optical Center SmartBuyGlasses CA

Why You Might Need Prism Glasses

What Are Prism Glasses?

 

Prism glasses are one form of treatment for some people who have diplopia or double vision. Find out how prism glasses work (and whether you may need them) using this informative guide.

 

How Do Prism Glasses Work?

 

With normal vision, light enters each eye through the cornea. It then falls on the retina, the light-sensitive tissue at the back of the eye. As light falls on the same part of the retina of each eye, the eyes are able to work together, causing the brain to see a single image.

With double vision, two images are seen. This is because the light falls in different places on the retina of each eye, and the brain is unable to account for the difference in images. 

When wearing prism glasses, light is bent before it travels through the eye and redirected so it falls correctly on the retina. The brain does the rest, fusing the two retina images together to produce one clear picture.

 

Who Might Benefit From Prism Correction?

 

Sufferers of these conditions often experience double vision:

  • Eye muscle problems, such as myasthenia gravis, Graves’ disease, or strabismus (crossed eyes or wall eyes).

  • Neurological issues, such as head injuries, stroke, migraine, or tumors.

  • Nerve-related problems, like multiple sclerosis or diabetes mellitus.

It should be noted that double vision has many causes, and a prism is not an all-encompassing solution. As it can be a sign of a serious health condition, it's important to find out what's causing double vision before going straight to prism glasses.

See a doctor immediately if your double vision is new, caused by eye misalignment, or happens for unknown reasons.

 

Your Prism Prescription and Eyeglasses

 

Like normal eyeglasses, a prism is measured and prescribed with a unit of measurement called prism diopters (presented as 0.5PD, 1.0PD or 1.5PD, for example). Depending on the nature of your double vision, the prism is placed vertically, horizontally or diagonally in one or both lenses of your eyeglasses.

Sometimes, a temporary Fresnel prism (a thin press-on vinyl sticker) is fitted over the front of your eyeglasses. With a Fresnel prism lens, the prism is slightly visible. This isn't ideal for long-term use, but it does allow you to test drive a prism and see how it works. Fresnel prisms are also used when the prism prescription isn't stable and may soon change.

 

Can You Drive With Prism Glasses?

 

If you have prism glasses, you will have to inform your national driving authority, such as the DVA in the USA, or DVLA in the UK. They will need you to confirm that your double vision has been rectified - if it has, you will be able to drive, but only with your prism glasses on.

 

What Do Prism Glasses Look Like?

 

Eyeglasses with a prism are not hugely distinguishable from regular glasses, although the lens on one side may be thicker and more noticeable, with multiple lines crossing the lens.

 

How Long Do Prism Glasses Take To Work?

 

According to eye care professionals, generally it only takes 2 to 3 days for the eyes to get used to prism lenses. However, not everyone’s eyes are the same; in some cases, it could take up to 2 weeks for the eyes to properly adjust. Read more about how to adjust to new glasses here.


Read more about eye health from our article selection here, or consult our ‘Ask the Optician’ eye health FAQs here.

Was this article helpful? Thanks for your feedback!

Sign up for a free, exclusive membership

Register
OR
Sign in with Facebook

Exclusive Features

  • Order Tracking
  • Easy Re-Order
  • Saved Prescriptions
  • Express Checkout
  • Exclusive Discounts and Sales
By joining SmartBuyGlasses you agree to the Terms & Conditions

Sign up for a free, exclusive membership

What is your gender?

When is your Birthday?

Sign up for a free, exclusive membership

What is your gender?

When is your Birthday?

Subscribe to our Newsletter
By joining SmartBuyGlasses you agree to the Terms & Conditions

Thanks,

You are all set!
Visit Membership

Forgot Password

Please enter your email below. We'll send you a link to reset your password.
Send E-Mail

Having trouble?

Don't hesitate to Contact us

Forgot Password

We've sent an email with instructions on how to reset your password.

If you don't receive instructions within a few minutes, check your email's spam and junk filters.

Having trouble?

Don't hesitate to Contact us

Reset Password

Password must be at least 8 characters.
Save and Sign In

Having trouble?

Don't hesitate to Contact us

STYLE FINDER

Get personalized eyewear recommendations with our style finder and find the perfect pair for you.

Are you shopping for a…

Woman

Man