Abstract

Stand magnifiers are popular aids, frequently prescribed in vision rehabilitation services, and are most commonly purchased by patients or their relatives over the counter. Thus, they serve as the only aids for many of the visually impaired who do not gain access to low vision services. The popularity of stand magnifiers is a result of the fact that they are easy to use and simple to learn to use. The fixed object to lens distance provides a stable and focused image at all times. Despite these advantages optical lens stand magnifiers have numerous shortcomings. The main complaint directed at existing stand magnifiers is the need to bend over the magnifier in order to be able to read through it (Spitzberg et al., 1989), which is very tiring for elderly users. The postural problems associated with stand magnifiers also complicate the attainment of proper illumination. The user’s head tends to block light from above, while the need for light access through the sides of the magnifier makes for an uncomfortable and difficult grip. One novel design incorporating a prism to tilt the image's angle has been reported by Spitzberg et al. As is the case with all other optical magnifiers, stand magnifiers are also limited by distortions and vignetting. Typically their field of view is smaller than other equivalent power devices (Cohen & Waiss, 1991), preventing binocular use in most cases.

© 1995 Optical Society of America