What Do Prisms For Low Vision Do?
Many people who suffer from low vision experience a decrease in their peripheral vision and visual field. In conditions such as scotoma, patients can develop non-seeing areas in their visual field which make many tasks more difficult. Prism lenses can also help patients who have central vision loss, double vision, and symptoms associated with that such as headaches and balance issues.
While for most low vision patients the vision loss cannot be reversed, there are devices, such as prisms, designed to help improve their vision and allow them to regain some measure of their independence.
Prisms also help reduce the eye strain that can be caused by using close vision with glasses for extended periods of time. For patients who need high levels of magnification, prisms allow them to keep working for extended periods in comfort.
These prisms, also known as fresnel prisms, are made of optical polyvinyl chloride, which increases the chromatic dispersion and produces a loss of contrast. These effects have been found to be helpful for patients with blurry and diplopic vision with distance viewing.
For visual field issues, the prisms can focus the image into a part of the retina unaffected by vision loss. Additionally, if the eyes have different visual capabilities, prism lenses can help equalize things and help avoid eye strain.
