There are several types of Magnifiers: hand-held, stand, illuminated stand, pocket, & illuminated pocket. In each category, these magnifiers can range in powers from 2.5X to 12X. It is important to know that lower powered (weaker) magnifiers are larger and wider. For higher powered (stronger) lenses, as the power increases, the width of the lens gets smaller and smaller, as does the field of view. Note: In general there are 2 measurements: in powers (x) and in Diopters (+). Four Diopters equals 1 Power.
When using a hand held magnifying glass, you need to know that these lenses come in different powers or strengths. It is important to keep in mind that as the power of the lens gets stronger, the diameter of the lens gets smaller. Another way to say this is, the larger the lens, the weaker the power will be.
The lens will also have to be held closer to the paper as it gets stronger. Often when persons use very strong lenses, this distance from the paper can become frustrating because if the lens is moved slightly it may go out of focus. It is hard to maintain an equal distance from a piece of paper unless the entire paper is flat and you have a steady hand.
This is one of the reasons why a stand magnifier (a magnifier with little legs on it) is often chosen. The legs on the magnifier are preset with the correct focal distance from the paper and the person can easily move this stand magnifier across the paper to read. When using a hand-held magnifier, however, it is important that the person does not look through their bifocal lens to read. When using a stand magnifier, it is important that they look through their bifocal.
The patient's current level of vision is the absolute determining factor for selecting the required power level, and a simple reading chart (the Mattingly Chart) helps us to determine the strength of magnification a patient would need.
The quality of a magnifier will affect the patient’s ability to read. By looking through the lens at a square grid, if you see the lines wavy, especially around the edges, you know there is distortion in the lens. This will be very apparent in lower cost magnifiers. When there is distortion in the lens, the patient experiences greater eye fatigue, and contributes to eye strain. This means reading for shorter periods of time. It is important to select a magnifier of the proper strength and of top quality, such as the line of Eschenbach magnifiers. (see article: “Why are Eschenbach products better than similar items?”)
“It doesn’t clear up my vision!”
We would love to offer patients with Macular degeneration or other low vision problems, devices that will clear up their vision problems. We offer the best quality magnifiers available, whether they are optical glass or video magnifiers. A magnifier will magnify, that is make larger, words or images. The distortion that occurs, for example in the vision of a patient with Macular Degeneration will still be there. The purpose of a magnification aid is to make the text or image large enough for the patient to be able to discern what it is by working around the area in their field of vision that is distorted.
Full page magnifiers:
Southwest Low Vision often gets asked: What about a full page magnifier? I want to be able to see a full page at once! I don't want to move a magnifier back and forth across the page!
Full page magnifiers are called ‘Fresnel’ magnifiers, and they are constructed of plastic with grooves imprinted on them. For patients who have Macular Degeneration these grooves reflect back the light creating glare, and the grooves act much like Venetian blinds, preventing the patient from seeing through. A comment we hear is: “It looks all blurry”.
We all think that we read the whole page at once, but the reality is our eyes keep moving over the page, to give us the whole picture.
The New Reality:
As a low vision patient it is now the magnifier that moves over the page to give us the picture. We tell our patients that this is the ‘NEW NORMAL’!
Most Commonly Selected Magnifiers
The magnifiers that are most commonly selected by our low vision patients are illuminated hand held (Mobilux LED) and illuminated stand magnifiers (System Vario Plus).
The type of light which most of our patients favor is the LED or light emitting diode. It has a white light which is much easier to see by than a standard incandescent light! The LED has no bulbs to change (lowers user costs) and takes less power from the batteries (lowers user costs).