The prism in prescription glasses is used to correct double vision or strabismus.
Unlike standard lenses, a pair of glasses with prism correction bends the light entering the eye to assist in proper focus, especially when the eyes are not aligning together as they should.
Here, we have discussed all the implications related to the prism eyeglass, how it reflects light, what to know before buying, and other alternatives to prism eyeglasses.
If you're experiencing specific vision issues, prism glasses might be a beneficial solution.
What are Prism Prescription Eyeglasses?
Prism Prescription Eyeglasses are used to correct the vision of people who suffer from double vision or diplopia. These glasses use lenses that are crafted to gently shift the way light enters the eyes. Prism lenses change the direction of light so both eyes see the same image and help the brain to combine them into a clear picture.
Prismatic lenses are triangular in shape and made out of plastic or glass. Prism eyeglasses do not include focusing power unless the patient also needs correction for nearsightedness or farsightedness.
Normal eyeglasses for nearsightedness or farsightedness are used to correct refractive errors, but prism lenses adjust the way light enters the eye.
The placement of prism lenses can be base out, base in, base up, or base down as per the patient's eye health. By adjusting the light path, lenses can alleviate the strain and discomfort associated with various alignment issues.
How Prism Lenses Help To Correct Eye Alignment
For those experiencing double vision, prism glasses are typically prescribed as a means to combine two separate images into one. This correction is vital for a variety of vision problems where the eyes do not align properly, such as strabismus or convergence insufficiency.
Prism lenses work by shifting the image into a position where both eyes can see it as a single, clear image, thus reducing the symptoms of double vision and helping the wearer regain normal visual function.
When are prism lenses prescribed?
Prism eyeglasses are prescribed to those patients who suffer from a special situation called binocular vision difficulties. They are used to correct how the eyes work together and are often recommended in the following cases:
- Strabismus (misaligned eyes)
- Binocular Visual Dysfunction
- Myasthenia gravis
- Eye muscle disorders,
- Convergence insufficiency
- Neurological conditions that affect eye movement
- After a stroke or brain injury that impacts vision
Sometimes, a few people are born with this type of double vision.
But sometimes it may happen due to neurological conditions like Stroke, Migraine, or Head injury, Diabetes mellitus, & Multiple sclerosis.
This type of vision impairment can be due to conditions that affect the muscles or nerves controlling eye movement, leading to misalignment.
In such scenarios, an optometrist might prescribe prism glasses to correct the misalignment and alleviate the discomfort.
What’s the Process for Getting Prism in Eyeglasses?
Obtaining a prescription for prism eyewear starts with a thorough eye examination. During this exam, your eye care professional will assess whether prism correction is necessary and calculate the precise prism diopters needed for your lenses.
Your ophthalmologist may do one or more tests to identify the value of your eyeglasses.
Hirschberg test:
This is the simplest and quickest screening tool to assess eye alignment. In this, an eye care professional uses a small light to identify the refraction in your eyes. They shine the light directly at your eyes while you look straight ahead and calculate the reflected light.
Krimsky test:
This test is used to measure the degree of deviation in the eyes. This will help in calculating the exact prism value required for eyeglass prescription.
In this, the Doctor puts Prism lenses of different strengths in front of the misaligned eyes and passes the light through them. They observe the corneal light reflex using a different prism lens and understand the shift of the light reflex to the correct position.
Cover tests:
The cover test is used to understand the working of the eyes together. This will detect how the eyes move and focus after converging one eye.
When the cover is removed, the doctor watches for eye movement that shows the eyes are not naturally aligned. There is an alternative cover test also to detect latent deviations (called phorias).
How Do You Read a Prism Prescription?
After receiving a prescription for prism glasses, you will find 2 types of prism correction values measured in prism diopters.
Prism Power:
Prism eyewear power is also calculated in the same diopter system(from 0.5PD, 1.0PD, 1.5PD, and so on), just like regular eyewear. The higher the number, the more correction your eyes need to work together properly.
Base:
An optician uses this to simply tell about where to place the thickest part of the prism in your lens. Depending on your double vision, the prism is placed vertically, horizontally, or diagonally in one or both lenses of your eyeglasses.
This determines where the light gets redirected to help your eyes align correctly. You might see Base Out (BO) for the outer edge, Base In (BI) for the inner edge, Base Up (BU) for the top, or Base Down (BD) for the bottom.
Do Prism Glasses Look Different from Regular Glasses?
Yes, prismatic eyeglasses are divided into two separate parts. One lens looks normal, but another one has a fitted prism lens.
In one lens, a temporary Fresnel prism (a thin press-on vinyl sticker) is fitted over the front or back of your eyeglasses. These types of glasses (made from a Fresnel prism) are not ideal for long-term use, but they are a good option to get relief from double vision. These lenses are also used when there is a chance to change the prism prescription soon.
It is always recommended to buy a thicker frame to hide your prism lens.
How to Pick the Best Frames for Prismatic Eyeglasses
You can't just pick any stylish frame and expect it to work well with prism lenses. These prescribed lenses need proper support to sit correctly and feel comfortable all day long. The wrong frame choice can leave you with uncomfortable glasses and an unflattering look.
You can choose frames with sturdy construction that won't bend, warp, or slide down your nose under the extra weight.
You can also understand which frame is best suited for your face shape.
Addressing Concerns and Questions
When considering prism eyeglasses, many people have questions about how they might affect depth perception or if they'll fit comfortably within their chosen glasses frames. Prism eyeglasses are carefully crafted to bend light, helping to correct vision issues that standard lenses cannot.
Are There Side Effects of Wearing Prismatic Glasses?
For some individuals, the effects of wearing prism glasses can include initial discomfort such as eye strain or eye pain. As your eyes adjust to a new way of seeing, these symptoms typically diminish over time.
If you experience persistent discomfort, it's advisable to schedule an appointment with your eye care provider. They will again identify the right fit of your eyes.
Is Prism Eyewear a Long-Term Solution for Your Double Vision?
Prism eyeglasses are a great solution for your double vision, but they can’t fix the underlying problem. For some people, this temporary relief is exactly what they need. For others who want a more permanent solution, you can talk with your doctor about vision therapy.
Costs and Investments In Buying Prism Prescription Glasses: X
The cost of buying prism eyeglasses can vary depending on the degree of prism correction required and the number of prism diopters prescribed. Prism lenses are a custom solution, often resulting in a higher price than standard eyeglass lenses. The complexity of creating a lens that can accurately redirect light to improve vision justifies the investment for those who need it.
It's important to consider that prism glasses are not just a purchase but an investment in your vision and quality of life. Upfront cost of buying an prescription glasses may be higher, but they are good to improve vision quality and overall comfort.
Life With Prism Eyewear: Tips and Insights
Adapting to life with prism glasses can take time, but there are several strategies that can ease the transition. Start by wearing your new glasses in a safe, familiar environment to allow your vision to adjust. It's also helpful to engage in activities that require a range of visual focus, such as reading or using a computer, to improve your adaptability to the lenses.
Be patient with yourself during this period; it's not unusual for it to take several weeks to fully adjust. Keep in regular contact with your eye care professional, who can provide guidance and reassurance as you get used to your new prism prescription glasses.
Adjusting to Daily Life While Wearing Prism Glasses
Activities that rely on depth perception, like driving or playing sports, may initially feel challenging. Give yourself time to adapt by gradually increasing the duration you wear your glasses, and be mindful of any changes in your vision as you go about your daily activities.
Communicating with friends and family about your adjustment to prism glasses can also be beneficial. They can offer support and understanding as you navigate this period of change.
Maintaining and Caring for Your Prism Prescription Glasses
Proper maintenance is essential to ensure the longevity and effectiveness of your prism prescription glasses. Handle them with care, always using both hands to put on and take off your glasses. Clean the lenses regularly with a microfiber cloth and lens solution to prevent scratches and keep your vision clear. When not in use, store your glasses in a protective case to safeguard them from damage.
Avoid exposing your glasses to extreme temperatures and chemicals that can harm the lens coatings. Regular check-ups with your eye care professional are also important to ensure the prism correction remains accurate and effective. By following these simple care guidelines, you can maintain the quality of your prism glasses and enjoy the benefits they provide.
Final Reflections on Prism in Prescription Glasses
So, the prism in prescription eyeglasses is designed to correct the vision of individuals who have a double vision problem. The prism eyewear can bend light coming from an object on the retina based on the correct eye. So a patient will see a single image rather than a double image.
To identify, prisms of different strengths are used to calculate the deviation in your eyes. These lenses are made of plastic or glass to redirect the path light enters the eye.
The complexity of the prescription will depend on the degree of misalignment and may involve Fresnel prisms or a progressive lens to suit your unique visual needs.
As for the final considerations, remember that prism glasses can vary widely in aspects, such as the amounts of prism needed for one eye or both eyes. These glasses are not just medically reviewed tools for vision correction; they also encompass a range of tests like prism and alternate cover, Maddox rod, and cover tests to determine the exact requirements.
With proper care and adjustment, prescription glasses with prisms are a great option to improve your vision quality and eye misalignment. This is supporting a journey towards a clearer, more aligned visual experience.
Hopefully, you found this article helpful. Please check out our other eyecare blogs. Thanks for stopping by.