What Are Prism Lenses?
Most patients who need eyeglasses to address nearsightedness or farsightedness are prescribed spherical and cylindrical lenses. These provide patients with excellent focus by correcting for refractive errors, so light reaches its destination.
When a patient’s binocular vision — the eyes’ ability to work together to create one clear image — isn’t well developed, a misalignment between the two eyes occurs. This can cause double vision, also known as diplopia.
When the eyes are misaligned, they struggle to work together to create a single image. Instead, they send two images to the brain, one appearing higher, lower, or to the right or left of the other image.
Prism lenses are required when a person has double vision, as the eyes are misaligned and the brain cannot fuse the two images into one single clear image. These lenses correct the misalignment as they move the perceived position of one image.
For example if you see two images and one is higher than the other, the prism lens will move the one image downwards - allowing the brain to fuse the images and removing the double vision.
Prism Lenses to Help Your Vision
Prisms are an integral part of vision therapy, which consists of customized exercises and lenses to improve visual processing by retraining the brain and eyes to work together. Prisms improve patients’ depth perception and spatial perception.
During the therapy sessions, your eye doctor will fit you with prism glasses, provide instruction, and ask what you are seeing and experiencing. These responses will provide them with valuable information on the prisms’ effectiveness.
Below are the types of exercises you may be asked to perform during a vision therapy session to test how well the prism lenses are working.
- Balance and depth perception - For this, your eye doctor might ask you to walk to a wall or down the office’s corridor, or to hold an object and look at the top of it from an arms-length distance.
- Peripheral Vision - While walking or holding an object, you may be asked to identify objects on either side while looking straight ahead.
- Balance/coordination - An exercise could involve looking straight ahead while slowly walking, step by step, toe to heel while maintaining your balance.
Prism lenses and the vision therapy exercises stimulate your brain, gradually developing a stronger eye-brain connection. Your eyes will learn to work together to regain clear and comfortable vision. This, in turn, will lead to improved balance and coordination, even when you are no longer using prisms. If you have been experiencing double vision, imbalance or depth-perception problems, schedule an appointment with Calgary to discuss how vision therapy involving prisms might help.
At Calgary we will gladly answer your questions about the role prism lenses play in vision therapy.
At Browz Eyeware, we put your family's needs first. Talk to us about how we can help you maintain healthy vision. Call us today: 587-600-0644 or book an appointment online to see one of our Calgary eye doctors.
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