Low vision devices vary for the same reason a carpenter carries so many different tools: each is good for a different task. Depending on the job, a carpenter may use a hammer, a wrench or a screwdriver. Likewise, a visually impaired patient may use a magnifier to read a pill bottle, a telescope to watch television, and a video magnifier to read a book. Each low vision device has its own set of tasks for which it is ideal and many people often use multiple devices.