Appropriate low vision aids are then presented to the patient and the practitioner evaluates the patient performance with each device. Thorough training in the use of each aid is critical to successful adaptation. To depend solely on visual acuity or visual field measurements invites misconception. Do not assume the primary eye care provider will refer for low vision assessment, many do not realize the potential benefits. No single aid can meet all needs due to magnification limits, focal distance, field of view, or portability.
Telescopes are compound lens systems which allow high levels of magnification at greater distance.
The field of view is generally limited to 5 o - 15 o . Common uses include watching TV, reading street signs, or viewing speakers at social activities. Some models provide up to 100 X magnification. They provide a larger field of view and more comfortable working distance than is possible with a comparable magnifier. Adaptive computers and free standing optical character recognition systems could also be included in this area.