
What are prism lenses?
05 September 2024
Prism lenses are a special type of optical lens designed to correct eye alignment problems, such as diplopia (double vision) and other forms of strabismus. Unlike traditional lenses, which only correct refractive problems such as nearsightedness or astigmatism, prism lenses bend light so that the eyes can align images correctly.
How do they work?
Prism lenses work by altering the path of light entering the eye. Normally, when we look at an object, both eyes must align images precisely so that the brain can fuse them into one. However, in people with eye alignment problems, the eyes do not point in the same direction, which can cause double vision.
The prism in the lens bends light in a specific direction, compensating for the misalignment of the eyes. This allows the brain to receive a single, clear image, eliminating double vision and improving visual comfort.
Prism lenses are commonly prescribed for the following:
- Diplopia: People who see two images instead of one due to eye misalignment.
- Strabismus: When the eyes are constantly or intermittently misaligned, which can cause vision and perception problems.
- Oculomotor palsy: Patients with paralysis of the muscles that control eye movement may benefit from prism lenses to better align their vision.
- Eye strain: Some people who experience extreme eye strain due to mild eye misalignment may also benefit from wearing prism lenses.
Adjusting to prism lenses may take some time. At first, some people may experience dizziness or feel that images look unusual. However, with consistent use, most people adjust and find that the lenses significantly improve their vision.
Like any corrective lens, prism lenses require proper care. It is important to keep the lenses clean and free of scratches to ensure clear vision. It is also advisable to visit your ophthalmologist regularly to ensure that the prisms are properly aligned and that your prescription remains correct.