Prism Glasses

Light normally enters your eyes through the cornea before it reaches the retina. In eyes with normal vision, the light hits the same place on both retinas, which creates a single image in the brain. People with double vision have light reaching different parts of each retina, which produces two separate images. Prism lenses bend light and redirect it to reach precisely the same spot on each retina. Then the brain steps in and combines the two images into one crystal-clear image.

You should only experience one side effect from prism eyeglasses: corrected vision. If prism glasses wearers experience wandering or misaligned eyes, headaches, pain accompanying eye movement, facial or eye pain, nausea, or seeing double images, they should see an eye doctor immediately. These side effects can be caused by misaligned frames, an incorrect prescription, or a change in the body, but it is important to figure out what is causing these symptoms.

The cost of your prism lenses will depend on the frames you choose, but will not be much more expensive than any other prescription glasses you order from EyeBuyDirect. Even if you choose high index lenses for strong prescriptions, when you order from us, you’ll save hundreds of dollars compared to what prism lenses cost elsewhere.

Prism lenses look just like any other eyeglasses! The thickness of the lens will vary based on the prescription, so some will be thinner than others. However, the lenses in prism glasses are ground to a different shape than most other prescriptions: the apex of the lens will be thinner than the base. This is usually unnoticeable unless you are inspecting the glasses carefully.

Yes! While patients with double vision are often advised not to drive, if their diplopia can be controlled with prism glasses, they should have no trouble doing so safely. One of the great benefits that come with correcting double vision is being able to see clearly, which makes driving much safer.

The thickness of prism lenses will vary by prescription, but generally speaking, they are not very thick–certainly not noticeably thicker than other prescription glasses. A very high prism prescription may be noticeably thicker towards the bridge of the nose, but using high index lenses can ensure a thin, lightweight lens. If you are concerned about the appearance of thick lenses, you may want to choose a full-rimmed frame to conceal the edges.

People who are prescribed prism lenses will have a short adjustment period where their eyes are getting accustomed to the glasses. For most, two to three days is all it takes, although some rare cases may take up to a couple of weeks. Nonetheless, if you don’t feel like you are adjusting to them at all after three or four days, the glasses may require an adjustment or your prescription may be off. Either way, you’ll want to see an eye doctor to double-check.

Prism prescriptions will have two values: prism and base. The prism measurement refers to the amount of prism required to make up for eye alignment issues. This will be a number between 0.5 and 5.0. Base refers to the direction of the prism, indicated by the relative position of its thickest edge (the base). These are noted with the abbreviations BO=Base Out (toward the ear), BI=Base In (toward the nose), BU=Base Up, and BD (or BDn)=Base Down.

Understanding these numbers and values is less important than entering them correctly when you order your glasses online. We make it as easy as possible for you and are available via live chat if you need help.

An eye doctor can quickly adjust eyeglass frames that are not aligned properly. If this doesn’t help, you’ll need to have your lenses checked. Mistakes can happen during the cutting of lenses, which will mean needing to have the lenses replaced. However, if the lenses are cut properly and the glasses are still not working properly, you will need to have your eyes reexamined to get the right values for your prescription.

Absolutely not. There are plenty of myths about things that will hurt your eyes, but none of them are true. The worst thing that can happen if you are wearing the wrong prescription is blurriness or a temporary headache.

Medicare does not cover the costs of prism glasses and only helps pay for eyeglasses with corrective lenses following cataract surgery. Moreover, the glasses that Medicare covers must come from a supplier enrolled in Medicare.