Complete Guide on Prism in Eyeglasses

Double vision trouble? Has the doctor prescribed you prism glasses?

Wondering how the triangular solid geometric object gonna help you in improving your eyesight. Don’t fuss over, it’s not that complicated to understand. You might be new to this optical term but these prescription glasses were said to be invented in around 1930s.

The predominant function of these glasses is to make both the eyes work together. In short, it’s a fool tool for your brain to direct eyes, rightly. Again don’t get confused, know it better…

What are prism glasses?

The most common term you come across when you go through your prescription details or fill out a prescription online, prisms glasses are special optical tools that eliminate the problem of double vision or diplopia.

For the two separate images formed for a single object in diplopia, Prism glasses effectively bend light and make them fall on the same part of both eyes. So, that both eyes work together to form a single sharp image.

How does prism glasses work?

We all have learned in school how the prism works, right? When the light gets entered, the crystal clear pyramid emits rainbow colour spectrum. But don’t get mistaken that prism eyeglasses will work the same and show you the world painted in rainbow colours. Prism in glasses actually helps to realign the images and manage the problem of double vision.

Prism glasses gives right assistance to the brain and help the eyes to see in a proper direction. The properties of the prism is used to mould the image where the brain is being tricked to do the visual processing, in such a way that the two images your eyes see, gets fused into one thus eliminating double vision, smartly.

Vertical or horizontal prism (depending on the condition) would be added to your glasses to correct the dysfunction.

You can find a small triangle shape (Δ) in your prescription that indicates the need for prism correction.

Spectacle Prescription
  Right Left
Sphere pl -0.25
Cylinder -1.00 -1.00
Axis 99 58
Add +2.50 +2.50
Hor Prism 2BO 2BO
Ver Prism
PD 60-59

Note: This is not a prescription for Contact Lenses

Who need prism glasses?

Average glass wearers around the world do not require prism glasses but there are few scenarios where your eye doctor would recommend you this additional attachment on lenses. Sometimes the eyes and brain fail to communicate rightly. The eyes are unable to work together and both the eyes see two identical images, instead of one whole picture. This vision condition is termed as diplopia. A person suffering from diplopia will be generally prescribed prism glasses. Diplopia patient might also witness blurred vision. This kind of vision condition usually occurs due to the improper functioning of the muscles around the eye.

Prism glasses are also prescribed in cases of brain injury or brain stroke as it generally affects the vision. These glasses are also recommended to athletes who would benefit with an enhanced vision that can improve their performance.

Prism lenses also seem to help patients with hemianopia. It is a vision condition where the person is partially blind. It affects half of the vision field either left, right or both eyes. Patients with severe spondylitis or having orthopedic chin down posture can also be benefited with prism glasses.

In short,

Who can be benefited?

  • Anybody suffering from eye muscle problems like strabismus, wall eyes, Myasthenia Gravis and Graves’ disease
  • Anybody facing some brain related issues like head injury, stroke, brain tumor or migraine
  • Anybody suffering from nerve related issues like diabetes mellitus or multiple sclerosis

Can prism glasses cause side effects?

Despite wearing prism glasses, you can still witness double vision, headache, misaligned eyes, eye pain and other such related symptoms. What could be the reason, have your prism eyeglasses stopped working or is it some kind of side effect? The wise and the right option in such situation is to consult your eye doctor.

The two prime reasons for such condition could be either misalignment of lenses or expired prescription. Sometimes due to regular use, prism lenses can get misaligned, readjusting can make the situation better. Wrong or old prescription for prism correction can also have a negative impact on your vision. Make sure your prescription is up to date. No matter what is the reason, it is better to get consulted by an eye doctor.

Prism lenses are made up of thin pieces of optical material that are used in making prescription glasses.

FAQs related to prism glasses

1. Can prism glasses be worn while driving?

Double images during driving can be dangerous. So it’s usually recommended to wear prism glasses and stay safe. However, consulting your eye doctor would be a wise call.

2. Is it necessary to wear prism glasses all the time?

If it’s offering enhanced and strain-free vision, then why not? Initially, you might find difficult but soon you will get used to these glasses.

3. How long does it take for the eyes to adjust to prism glasses?

According to eye care professionals, generally is just takes 2 to 3 days for the eyes to get used to prism lenses. But in very few cases it might take around 2 weeks. However, if you don’t feel comfortable even after 3 to 4 days, it is advised to consult your eye doctor.

4. Are prism glasses noticeable/thick?

The apex of prism lenses is thin while the base is thick, so it is kind of noticeable. However, in case of high index material, prism glasses are made up of ultra thin material which improves the appearance and doesn’t make it much noticeable.

5. Can a person with prism correction wear contact lenses?

Some patients can wear while some can’t. The best advice is to consult the doctor who tested your eyes because only your doctor would likely tell you if your eyes are suitable for wearing contact lenses or not.

6. How much do prism glasses cost?

The cost of prism glasses depends upon the lens type and lens power. You may send your prescription or contact us to know the cost.

When to talk to your doctor about double vision?

  • When it’s new and comes to your notice
  • When it caused due to misalignment of the eye
  • When you witness it due to some unknown reason

If your eyes do not work properly together, it can create a lot of trouble. Take an appointment immediately and get your eye diagnosed.

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