Its light weight allows it to be worn comfortably for hours. A separate, rechargeable battery pack operates the system for an entire day. The visually impaired might benefit greatly from telescopic lenses if only they could be used easily. Telescopes must be refocused whenever one looks from one distance to another, especially at close viewing distances where even slight movements can blur the image. As a result, individuals find telescopic glasses inconvenient and difficult to use.
Seniors often find it hard to learn to manipulate the devices.
Students find it difficult to look at the blackboard, then watch the teacher, and then look at their desk. Computer operators can't easily look at the monitor, then switch to the keyboard, a printout or another worker. It allows the visually impaired to perform visual activities much more efficiently and with greater comfort than ever before. Computer controlled infrared electro-optics measure the focusing distance many times per second while another computer controls a miniature motor that moves the focusing lens to the proper position. Special software helps to insure that the focus is prompt, accurate, and stable.