What is prism lenses?
Prisms, by definition, are triangular in shape, made for the purpose of dispersing light into a spectrum, or changing the direction in which light is reflected. Lens with prism is shaped in a way to bend the light that is coming into the eye. It makes images can be seen by the eyes/brain to a place that is more comfortable for the eyes, allowing for single, clear, and comfortable vision.
Why some people need prism lenses?
Some people suffer from severe binocular vision difficulties and double vision, mostly visual problems caused by: Binocular Visual Dysfunction, Strabismus, Myasthenia gravis, Graves’ disease, Convergence insufficiency; Neurological problems are caused by: Stroke, Migraine, Head injury, TumorDiabetes mellitus Multiple sclerosis.
How do prism lens works?
A prism added to eyeglasses bends light before it travels through the eye. The light is redirected to the right place on the retina in each eye. The brain then fuses the two images together to produce one, clear picture. This helps the eyes to perceive images in a way that single vision can be achieved— improving binocular vision, and reducing double vision, headaches, reading difficulties, and more.
What Does a Prescription for Prism Look Like?
A prescription for prism typically has two data:
- Prism. Like normal eyeglasses, diopters measure the amount of prism correction (from 0.5PD, 1.0PD, 1.5PD, and so on) and indicate how misaligned theeyes are.
- Base. Depending on your double vision, the prism is placed vertically, horizontally or diagonally in one or both lenses of your eyeglasses. The “base” is the thickest edge of the prism and tells the wearerwhere the light is redirected. It may be on the outer edge of the lens (Base Out, BO), the inner edge (Base In, BI), or at the top (Base Up, BU) or bottom edge (Base Down, BD).
