Low Vision Magnifiers Guide

businessman holding a magnifierMagnifiers can help people with low vision read text, distinguish objects and notice details that they would otherwise be unable to see clearly. Choosing the right magnifier can improve your quality of life and enable you to perform tasks that could otherwise be difficult with low vision. Finding a magnifier to fit your needs depends on the answers to several important questions including:

  • - What is the cause and degree of my visual loss?
  • - What task will I be performing when I require magnification?
  • - Are there any special features that my ideal magnifier should have?


In this guide we will explore all of these factors so that you can make an informed decision about what kind of magnifier will be most helpful in your day to day life.

cartoon of man holding a magnifierDetermining the Cause and Degree of Visual Loss

There is more than one cause for low vision and it's important to understand the cause and degree of the visual loss that you are experiencing before you can choose the appropriate low vision device. A qualified vision specialist or optometrist will be able to diagnose the cause and degree of your vision loss and also give you advice about devices and aides that are best suited for your specific condition.

Magnifiers are helpful for people that are experiencing visual loss in the center part of the retina, called the macula. This kind of visual loss is commonly a result of the normal aging process of our eyes but there are several other important causes including injury to the eye and certain medical conditions. Your low vision specialist can help you decide whether a magnifying device will be beneficial in your circumstances.

magnifier displaying the word solution How Strong Should My Magnifier Be?

The strength of a magnifier is based on its magnification power measured in diopters, usually expressed as (D) or "X". A 4D lens magnifies times 2 (2X) so the result is a magnified image that is 100% larger than the original. To learn more about magnification power and how it is determined, please refer to this Magnifier Glossary.

GLOSSARY OF MAGNIFIER-RELATED CONCEPTS

Diopter (D): A term used to identify the refractive (light bending) capacity of a lens. In magnifiers, there is a direct correlation between focal length and diopter. To find the diopter of a magnification lens, follow these steps:

With the eyes 10" above the lens, move the object to be viewed to the point the greatest distance below the lens where it remains in sharp focus. Measure this distance and divide into 1 meter (39.37"). The result is the diopter of the lens - e.g., if the object is at a 13" distance then it is a 3-diopter lens (39.37/13 = 3d). Each diopter increases the size of the viewed object by 1/4 (25%) when the object is at its full focal length from the lens.

Field of View: The distance across the lens surface to which the viewer brings both his eyes (note: eyes should be 10" above the lens). It is important to note that as magnification increases, meaning the lenses used are stronger, viewing areas and focal length decrease.

Magnification: The degree to which the viewed object is enlarged. Magnification is usually expressed by a number followed by an "x", the symbol used to express power or the size of the object in relationship to its actual size. The formula for calculating Magnification Power is:

MP = D (Diopter) + 1
4

Example: 20 D + 1 = 6X
4

Selecting The Right Magnifier:

1. Determine the desired magnification for your needs. Remember, as you increase magnification, you decrease both the focal length and the viewing area.
2. Check to find out the correct diopter you need to achieve that magnification.
3. Note the focal length and lens diameter that correspond to the magnification and lens diopter you have chosen, and make sure they are suitable for your task.
4. As a general rule, because the working distance will be less than 8" above 5 diopter, stereo microscopes are recommended for rework purposes only.

Tips on Proper use of a Magnifier:

To take best advantage of the comforts built into illuminated magnifiers, please keep these points in mind:

1. Use both eyes. Magnifiers are designed as "working tools". They can be used as comfortably as a pair of glasses.
2. Position the lens so that it is a proper distance from the work area, yet close enough for your eyes (8" to 10") so that you have the maximum magnification without distortion. Do not lean back away from the lens to increase magnification.
3. Chair height and work surface should be positioned so the operator can maintain good posture while working.

Source: Howard Electronic Instruments



Surprisingly, picking the right strength for a magnifier may depend more on what you plan to use it for than the degree of your visual loss. A very strong magnifier may make your eyes weary if you are going to be using it for extended periods of time. The best rule of thumb is to pick the lowest magnification level that will allow you to comfortably perform the task at hand.

Something else to note is that the stronger a magnifier is the smaller the area that will be magnified. That means that a very strong magnifier will not give you that wide field of vision that you would need to comfortably perform tasks where you need to "see the big picture" like reading a book or doing embroidery for example. This brings us to our next question:

bunny holding a magnifierWhat Kind of Magnifier Should I Be Looking for?

That depends on what you want to do with it! Magnifiers can be grouped into these basic categories:

  • Handheld Magnifiers- These magnifiers are usually small and lightweight. They typically consist of a handle attached to a lens, some include a built-in light source. The advantage of handheld magnifiers lies in their portability, they are best suited for on the spot magnification like when you need to read a restaurant menu or check your receipt at the grocery store.

    Hands-free Magnifiers
  • Hands-free Magnifiers- These magnifiers are convenient when you need magnification and the ability to use your hands for other tasks (other than holding a magnifier). They include: magnifying visors, LED readers, full-page magnifiers, and other types of hands-free magnifiers.
  • Stand Magnifiers- A stand magnifier is a magnifying device that is more stationary in nature than a handheld magnifier, it may sit on or near the stand magnifierobject that it is magnifying. While you may need to adjust the position or angle of a stand magnifier, it doesn't require you to hold it continuously which makes these magnifiers useful for extended tasks like reading a book or tasks where you want to have both of your hands free, like sewing. There are many kinds of stand magnifiers suited to different tasks and users. Gooseneck stand magnifiers sit on a table or desk and have an adjustable arm attached to the lens for easy positioning.
  • Low Vision Eye Glasses and Binoculars- These magnifiers are ideal for watching television or going to a show. They provide "big picture" magnification on your full range of vision for as long as you require it.
  • Video Camera Magnifiers- Also called "CCTV devices" these magnifiers focus on an item and then show that item magnified on a monitor or screen. Video camera magnifiers are available in many sizes, from small handheld devices to large, widescreen projection models. They can be extremely versatile with options to adjust the level of magnification and contrast.

handheld magnifierIlluminated Vs Non Illuminated Magnifiers

Another important consideration with any kind of magnifier is whether to choose an illuminated magnifier or one that depends on the light available in your surroundings. The advantages of an illuminated magnifier extend beyond the obvious added visibility that a built-in light source provides; a magnifier without illumination may cast a shadow on the area you are magnifying making it more difficult to view clearly.

Non illuminated magnifiers are required for magnification of television screens or computer monitors to avoid image distorting glare.

Screen Magnifiers - Magnifying Software for Your Computer

A different kind of low vision aid, a screen magnifier is software that works with your computer's graphical display to "zoom in" and magnify a portion of your computer screen. Additional features depend on the software but may include:

  • - Adjustable color and contrast controls for enhanced visibility
  • - Settings for larger sized icons and mouse pointer
  • - Voice to text capability and/or the ability to select text and hear it spoken


There are many excellent screen magnifier software packages available today, determine the features that you require and be sure to read consumer reviews of the software before you buy.

Magnifiers from Assistech

By now you are ready to start browsing and comparing magnifiers! Assistech carries a full range of magnifiers to fit every need. Use our Magnifier Wizard to help you get started or pick a category below:


Binocular
Binoculars
CCTV Magnifiers
CCTV Magnifiers
Handheld Magnifiers
Handheld Magnifiers
Hands-free Magnifiers
Hands-free Magnifiers
       
Magnifying Lamps
Magnifying Lamps
Pocket Magnifiers
Pocket Magnifiers
Screen Magnifiers
Screen Magnifiers
Stand Magnifiers
Stand Magnifiers

Video Demo


A mother shares a story of hope and independence concerning her low vision daughter and her experience with Low Vision magnifiers.



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