Telescopes, like binoculars, allow the user to see further away. For low vision applications telescopes can be prescribed as hand-held (monoculars) or mounted into a pair of eyeglasses (bioptics). They can be prescribed for one or both eyes and are available in fixed focus, manually focusable and autofocus versions. They are available in a range of powers and designs and their selection should be advised by the low vision specialist.
They are best used when stationary such as when watching television or at the theater. A bioptic telescope is mounted in the top portion of a pair of glasses and in some states, these are permitted to help people spot distant road signs, etc., when driving, among other tasks.
Magnifiers that contain only a single lens, whether they are handheld, stand or mounted into eyeglasses require that the material viewed be held at the focal length of the lens—usually very close to the eye. This may not be comfortable or natural for longer activities. Focusable telescopes can be adjusted for use at almost any distance from up close to very far away and hence, can allow the activity to be performed at more natural working distances.
In 47 states in the US, eligible visually impaired persons may be allowed to drive using bioptic telescope eyeglasses. These bioptic devices allow the driver to see further up the road to see signs, signals, other traffic and road obstacles sooner and give them more time to adjust their driving appropriately. The user drives looking through the regular eyeglass lenses most of the time and dips their head slightly to sight through the telescope when necessary, similar to the use of the side and rearview mirrors. The licensing process and regulations regarding driving with a bioptic device vary from state to state and must be done in conjunction with an optometrist familiar with prescribing bioptic telescopes. The low vision specialist will determine if the individual will be able to comply with the state’s bioptic driving requirements and would be successful with the device.