Adaptive technology advancements have improved magnifiers across the board. However, basic handheld magnifiers with an actual lens have not seen many advancements. We often view the handheld magnifier as the standard Sherlock Holmes clue-finding magnifier. The large lens on this magnifier increases the viewer’s field of vision when viewing text or other small items. Often, we think a larger lens gives us a more expansive viewing space. However, this is not necessarily the right way to think about a magnifying glass.
The power of a magnifier can be measured in several ways. The most common, “times magnification” or “power,” refers to how many times bigger an object appears when viewed through the device versus the naked eye. The “X” notation on many magnifiers represents the power provided by a given device. So a 3X means three times the magnification.
Lens Curvature and Focal Point
The magnifying power of a lens depends on its focal length (FL). The focal length depends on the lens curvature. Think of it this way the greater the curvature, the shorter the focal length, and the greater the power. When a lens is several inches wide, there tends to be less curvature resulting in more viewable space, but it will be relatively low in power.
Good examples of this are page magnifiers used to see a whole page of a book or magnifiers used to go over a television screen to allow a person from a distance to see the image better. Because both of these examples have very large surface areas, their magnification will be very low. Often from a 1x to 3x magnification power. When somebody first starts having problems reading a page, a magnifier might be the direction they go, thinking, “I will be able to see the whole page and not have to move it around.” But often, as their vision changes, the page magnifiers are not strong enough to allow the individual to see the letters clearly.
Low vision aids include various adaptive technology devices, such as magnifying reading glasses, handheld and stand magnifiers, loupes and small telescopes. Magnifying devices are generally either handheld or mounted on a stand, with zoom ranges from 2x to 10x.
Store-bought readers, often called cheaters, are readily found at popular pharmacies across the country and are frequently the first place an individual who does not wear glasses will turn when printed material becomes increasingly challenging to read. They come with lots of fun frames and are readily available. These lenses tend to be in the lower power ranges from 1x to 3x magnification. Reading glasses help bring small text into focus through magnification, making text appear larger. The downside is that when wearing these single-vision glasses to magnify text, they also magnify everything you view through the lens. While suitable for close work, they may distort anything in the distance. This can cause headaches and other eye strain-related issues. If you find you are using cheaters frequently, this would be the time to have your eyes checked by your eye care professional. Bifocals, to many, are a dirty word, but the advantage to bifocal glasses is they only change part of your field of view. If you view something through the base of the lens, the text will appear larger or clearer; but if you look through the top of your glasses, objects appear as they would normally.
Here are some key points to remember when choosing a magnifier:
How much magnification do you need?
What kind of tasks will you be doing with the magnifier?
What environment will you use the device in?
Do you need additional lighting with the magnifier?
Do you have other physical limitations, such as arthritis, carpal tunnel or tremors?
Magnifiers come in many shapes and sizes. Answering some of the above questions will help evaluate the best fit.
Handheld Magnifiers - are used for short-term uses such as reading a menu, price tag, or nutritional/cooking instructions on a box. They are portable and very versatile. Many models also have lighter options.
Stand Magnifiers – These are a better choice for extended reading periods. The stand rests directly on the page at the perfect distance to allow optimal viewing. Some models are also designed for reading and writing tasks such as writing checks, signing documents, or taking notes.
Other stand magnifiers may come on a swing arm to allow more flexibility ins tasks. This allows the user to sit more comfortably or to have their hands free to do tasks such as hobbies.
Monoculars and Binoculars – can help the user see items at a distance, often 15-30 feet away. These handheld telescopes are usually small enough to fit in a pocket. They are often used in an outdoor space or in a larger venue such as a classroom or concert hall. They allow users to see items such as street signs, menu boards and performers more easily. As these are often small fields of viewable space, they will require more scanning techniques and practice to be effective in daily use.
A low vision specialist may prescribe several different low vision optical devices for various tasks or help determine the correct type of device that will fit your needs. Also, these low vision evaluations are often covered by health insurance.
As adaptive technology continues to improve the way of life for those with vision impairment, we are here to help. Whether you need more information about a low vision evaluation or a magnifier, Contact us to get started.