Prism is a lens type specially designed to treat vision problems like double vision and other binocular vision issues. Just like a prism shape, prism lenses are triangular and are designed and placed to change the direction of light, or disperse the light into a spectrum. Prism lenses are made from plastic or glass material as with all optical lenses. Prism lenses are prescribed by optometrists and ophthalmologists, and can be made with or without the inclusion of refractive powers. Prism lenses can be special lenses that don’t necessarily contain focusing power; as a result, prism can’t correct refractive issues alone. Prism lenses ‘trick’ the eye and brain to believe an object is in a different location, to fix and improve vision alignment. This optical ‘trick’ helps the eye to perceive images differently to achieve single vision, improve binocular vision, reduce double vision, and reduce other difficulties that double vision causes, such as headaches. Depending on the way the eye is misaligned or turned, a prism lens can be based in, out, up, or down. Prism lenses are most likely to be prescribed for patients with severe binocular vision difficulties.
Visual issues that may be treated with prism lenses:
- Binocular Visual Dysfunction
- Myasthenia gravis
- Graves’ disease
- Convergence insufficiency
Neurological issues that may be treated with prism lenses:
- Head injury
- Diabetes mellitus
- Multiple sclerosis
Prism lenses bend light rays onto the retina, targeting double vision. This bending process allows the prism lenses to reduce double vision, and in some cases where refractive powers are included, correct refractive errors so that the patient may see a single and clear image while wearing prism lenses.