Can Prism Glasses relieve Eye Strain
Prisms work by bending the light before it enters the eye. This ensures that the light land on the same area for both eyes. Other than relieving double vision, prism glasses can also relieve eye strain. However, this also depends on what is the cause of the eye strain.
Who will benefit from prism glasses?
Patients who experience double vision can benefit from prism glasses. Double vision can be caused by misalignment of eyes, binocular vision disorder and more.
Prisms are not just for patients who experience full time double vision. There are also patients who experience occasional double vision. For example, seeing double vision only after several hours of doing near work such as computer work. Some can experience double vision once in a while, however as they get older, they notice that the frequency increase. There can also be patients who experience double vision only when they look towards extreme gazes. These patients may also benefit from prism glasses.
Just last year, we had a patient coming in complaining about double vision at her extreme gazes. To read more, click here.
Binocular Vision Disorder
Patients with symptomatic binocular vision disorders can benefit from prisms glasses. However, this depends on the type of binocular vision disorder.
Binocular vision disorder is when the eyes cannot work together properly. Patients who have binocular vision disorder can experience symptoms such as feeling hard to focus into a single image, blurry vision, double vision, eye strain or headache. Patient with binocular vision disorders may or may not experience symptoms. Some do not experience double vision but do experience eye strain.
As long as it is symptomatic, prisms can be given to relieve the symptoms.
Last year, a customer came into our shop complaining about blurry distance vision. Fortunately, he does not experience double vision. After a thorough eye check, our optometrists found out that he has one of the binocular vision disorder known as, Decompensated Heterophoria. It is a latent misalignment of the eye.
Even after correcting his eye power, he still finds that his distance vision is not sharp. After adding in the prisms, he could tell that the vision became clearer. Despite not experiencing double vision, he had other symptoms of binocular vision disorder and prism glasses can benefit him.
How does prism glasses looks like?
For prism glasses, prisms are grind into the lenses. Hence, it will not be visible on the lens surface. On the other hand, stick-on prisms are more visible. As compared to normal lenses without prisms, lenses ground with prisms will be thicker. The higher the amount of prisms ground
into the lens, the thicker and heavier the lens will be. Hence, higher index lenses and a smaller frame size are recommended to allow the lenses to be thinner and lighter.
However, there is a limit to the amount of prisms that can be ground into the lenses. If the amount of prisms you require is too high, stick on prism is usually used and other treatment methods such as vision therapy or surgery will be considered. The images below shows examples of vision therapy:
Can prism be done with progressive / bifocal
Yes, prism can be done with progressive or bifocal glasses. However, it also depends on the amount of prisms needed and whether the amount of prisms needed for distance vision and near vision are the same.
For progressive and bifocal lenses, there is also a limit to how much prisms can be grind into the lens. Furthermore, the prisms grind into progressive and bifocal will be the same for distance, intermediate and near.
Some patients may need prisms for distance but may not need any prisms for near. For patients who require different amounts of prisms for different viewing distances, progressive and bifocal lenses might not be suitable.
Just last month, we had a patient who only needed prisms for near. When we put prisms for her distance vision, she experienced discomfort and feel ‘weird’. Hence, progressive and bifocal glasses is not suitable for her.
Prism Glasses at Evershine Optical
At Evershine Optical, our optometrists will conduct a more comprehensive eye examination if you have symptoms such as double vision or eye strain. Other than checking your eye degree and eye health, we will also conduct a series of binocular vision test to check how well are your eyes working together and how much prisms are needed.
After the eye test, you will walk around with the prisms and see if the symptoms you complained earlier are relieved. Most importantly, to try if you experience any discomfort. If you experience discomfort, we will alter the prescription.
Occasionally, there are customers who cannot tolerate prisms. Prisms might have helped eliminate their double vision, however they feel that it is uncomfortable. In that case, other treatment methods such as vision therapy or surgery will be considered.
For first time prisms wearer, there will be follow-up visits after the collection of glasses. This is to ensure that the prism glasses prescribed are working and you are adapting well to it.
Binocular Vision Disorder at Evershine Optical
Just last month, we had a customer in his late 20s. He complained that he finds it hard to focus images into a single image at distance after spending 2-3 hours on his laptop. On his second visit with us, he complained that he starts to see double vision at distance after 2 hours on laptop. After prompting him with more questions, we realized that he have been on a more intense usage of near work than before.
After a comprehensive eye examination, we found out that he has one of the binocular vision disorders known as Divergence Insufficiency. It is a condition whereby the eye cannot properly diverge. The double vision he experienced could be due to stress or increase in amount of near work. We prescribed him with prisms which will bring the image towards his eyes. Hence, providing a single image without having him to focus so hard.
Experience eye strain or double vision? These could be symptoms of Binocular Vision Disorders. Book an appointment with us or WhatsApp us at +6588461234 to find out how you can relieve these symptoms.
- Erin C.J. Perfecting Prism. 2019. Review of Optometry.
- Yin C.T. Back to Basics, Part 1: Prime Yourself to Prescribe Prism. 2008. Review of Optometry.