Information Bulletin – Low Vision Aids
|There are dozens of different low vision aids to help improve the lives of people with albinism. Each aid has its own advantages and limitations. To get the most from a low vision aid, it’s important to see and understand what that device can and cannot do. Since different aids help with different tasks, the person with low vision will likely choose a mix of different low vision aids to accomplish all of his or her goals.
Tasks, goals, and technology change over time. Whether an individual has used low vision aids for years or just for a short time, the individual should periodically reevaluate the low vision aids he or she uses. This bulletin provides an overview of some of the most popular low vision aids in each task category, including magnifiers and microscopes for seeing things up close, telescopes for seeing things far away, non-optical devices, and strategies to improve one’s vision.
Glasses cannot fix low vision. Eyeglasses are not considered a low vision device unless they have a high reading “add” or contrast enhancement tint, but they deserve special mention here since glasses ensure that the person’s eyes see the clearest image possible and can easily focus at close distances. It is important for babies and young children with albinism to wear glasses to correct refractive error if they are nearsighted, farsighted, or have astigmatism. If a child with albinism who needs glasses doesn’t wear them, that child may tire easily and quickly give up doing certain tasks, and may even affect their development.
Short viewing distances
Beginning in infancy, people with albinism instinctively hold things closer to their eyes to see them better. Up until the age of five or six, this technique sufficiently compensates for low vision because books for young children already feature large print, or they can sit closer to the TV. As a result of using this desire of moving closer to what needs to be seen, children this age generally do not need low vision aids. Looking closely at objects does not hurt the individual’s eyes, and this strategy continues throughout life.
Near vision aids
Dome magnifiers, reading glasses, hand-held and stand magnifiers, and microscopes are near vision aids that help people with albinism read, look at pictures, diagrams, and maps, and accomplish other tasks that require seeing small details up close.Dome magnifiers are one of the easiest aids to use and arguably the most important for those with albinism [Figure 1]. Despite their seemingly modest ability to magnify print (1.7 to 2.2 times), in combination with a short viewing distance many reading tasks can be easily accomplished even in the primary grades of school. These magnifiers are also known as bright field magnifiers, paper weight magnifiers, and Visolett magnifiers.
Reading glasses help the user focus on text or other objects while holding the object close to the user’s eyes. Reading glasses allow the widest field of view for reading compared to other aids. Hand-held and stand magnifiers [Figure 2] enlarge close-up images, allowing the user to see small print and images at greater distances from the user’s eyes. There are many different styles and sizes of magnifiers useful for people with albinism.
Microscopes help people see smaller details than magnifiers produce. Microscopes enlarge close-up objects the same way telescopes enlarge far-away objects. Some telescopes and bioptic telescopes, designed for distance vision, also allow the user to refocus the scope for up-close use.
Distance vision aids
Telescopes can help people with low vision improve distance vision. Distance vision includes seeing a chalkboard in a classroom, seeing a menu board at a fast-food restaurant, or seeing the stage at a concert or the action at a sporting event. The two specifications that differentiate telescopes from one another are the magnification power and the field of view. Magnification power indicates how much larger an image appears through a telescope compared to how large it appears to the naked eye. Typical magnification powers for low vision telescopes range from 2x to 8x. When a person with 20/100 vision uses a 4x telescope, that person theoretically sees an image 4 times bigger than normal and, therefore, sees the same details a person with 20/25 vision sees. In general, the greater the magnification power of a telescope, the more fine detail the person with low vision will see using the telescope. However, as magnifying power increases, the field of view, or the size of the area enlarged by the telescope, generally decreases.
One of the most common low vision aids is the hand-held telescope, also called a monocular [Figure 3]. Hand-held telescopes come in a wide variety of sizes, magnification powers and prices. Hand held telescopes work best to quickly view a distant object, such as reading a sign or locating an object. Clip-on telescopes allow the user to slip the telescope over his or her glasses for hands-free use [Figure 4]. The clip-on telescope works well for the person who needs to use the telescope for extended time periods, such as for watching TV, a movie, or a live stage performance. The user can remove the clip-on telescope and use it as a hand-held telescope for quick viewing tasks.clip on telescope
A bioptic is a special pair of glasses with a telescope permanently mounted in the glasses’ lens. While looking straight ahead, a bioptic user sees a normal, unmagnified image through the glasses. Then by dipping one’s head slightly, the bioptic user instantly sees a magnified image through the telescope. This “bi-optical” system allows the user to rapidly switch between a normal view and a magnified view without ever using his or her hands. In some areas, some people with low vision can use bioptics to drive. (See NOAH’s “Low Vision Driving” bulletin for details.) A person with albinism can also use bioptics in the same situations he or she might use a hand-held telescope, such as seeing a classroom chalkboard. Hands-free use can help older students take notes in class more quickly and easily. Some bioptic users prefer telescopes in both eyes, while many users with albinism choose to have only one mounted telescope for their dominant eye.
One of the most common and simplest bioptic designs is from Designs for Vision [Figure 5a]. The Designs for Vision bioptic uses a telescope that extends about 3/4 to 1-1/2 inches from the front of the glasses’ lens and is 1/2 to 1 inch wide. Designs for Vision offers both fixed focus telescopes in a black metal housing and slightly larger focusable telescopes in a black plastic housing. They also make a bioptic telescope with a clear plastic housing to improve the bioptic’s appearance.
To make using a bioptic more discreet, Edwards Optical created the BITA system [Figure 5b]. This bioptic uses telescopes that are only 1/2 to 3/4 inches long and about as wide as a pencil. The telescopes also extend behind the glasses lens, instead of in front of it. The BITA design is much less noticeable than traditional bioptic designs, but the small telescopes also produce a smaller field of view.
Ocutech manufactures a bioptic system that mounts the telescope across the glasses’ bridge [Figure 5c]. This approach creates a wider field of view at higher magnification powers compared to conventional bioptic designs, plus offers a different appearance. Ocutech also manufactures an auto-focus bioptic, which automatically changes the focus as the user looks at different objects. The auto-focus bioptic is bulkier and more expensive than other bioptics.
When traditional optical low vision aids don’t help accomplish a task, electronic aids might help. Closed-Circuit Television (CCTV) systems help people who need greater magnification than reading glasses, magnifiers, and microscopes provide [Figure 6]. CCTV systems also allow the user to adjust the size, brightness, and contrast of the magnified image to best match the user’s vision. The user can even read white letters on a black background to decrease glare. CCTV systems have historically been far more expensive and far less portable than other near vision aids. Newer CCTV designs, however, such as the MagniCam®, are now smaller, more versatile, more portable, and less expensive then previous CCTV systems. Other electronic aids help users see far away objects.
Computers and Software
Desktop and laptop computers have advanced the ability of those with albinism to learn, communicate, and follow their chosen careers. Monitors are available in various sizes to suit an individual’s magnification needs.
Magnification can be changed in common software such as Microsoft Outlook, Excel, and Word. This can be done in a variety of ways such as directly changing it on the toolbar, or by going to the toolbar clicking on the “View” option. Another method that is to hold down the Ctrl key on the keyboard and then turn the small wheel in the middle of the mouse away from you or towards you to change the print size on many word processing and HTML screens.Specialized software is also available such as Zoomer, ZoomText, Kurzweil, or Big Shot. These have many advanced features such as magnification of specific areas on a page, or a split screen option.
Contrast enhancement aids
For people with albinism, bigger isn’t always better. Increasing the contrast of text is often more effective than increasing the size of text. Black felt-tipped pens and dark lined paper can make writing easier for some people with low vision. #1 pencils (as opposed to traditional #2 pencils) and bright-colored chalk can also help students with albinism.
Writing guides, which are templates with open areas where one writes, can help people write in straight lines, or with tasks like writing checks. Colored filters can make it easier to see certain colors. For example, a yellow filter can make light blue letters appear darker and easier to read. Lighting plays a major role in how well a person with low vision sees. Experimenting with different types and brightness of light, as well as the location of the light, can make tasks a lot easier. Keep in mind that too much light and too little light can both cause problems
Finding low vision aids
An optometrist or ophthalmologist who specializes in low vision evaluates the individual’s vision, and then recommends specific aids based on the patient’s needs and goals. Low vision clinics usually have a variety of aids on site to see and try as well as specialists trained to help the user get the most out of the new aid. Since everyone’s vision and goals are different, it’s important to try out as many aids as possible before choosing. Often, the newest or most expensive aid is not the best choice. If a low vision specialist only prescribes products from one manufacturer, the patient may want to visit another clinic featuring different products before buying an aid, especially when considering expensive aids, such as bioptics or CCTV systems.
There are catalog companies that sell some low vision aids, such as sunglasses, magnifiers, and hand-held telescopes. If the individual knows exactly what he or she needs, buying these products through a catalog may cost less than buying from a low vision specialist. Other aids, however, such as bioptics, require a custom fitting and prescription from an eye doctor.
The American Foundation for the Blind maintains a directory of U.S. low vision clinics. Call 1-800-AFB-LIND or visit www.afb.org for the list. State Vocational Rehabilitation offices or Blind Services Divisions can also help locate low vision clinics, and may even help find sources to help pay for low vision aids. In Canada, contact the CNIB at (416) 486-2500 or www.cnib.ca to find a low vision clinic.
Low vision aids cannot fix albinism or any visual impairment the way glasses or contacts can fully correct vision for normally sighted people. However, finding the right low vision aids can help people with low vision get the most out of their vision and realize their personal goals and dreams.
Consultants for this bulletin include Sara Appel O.D., Associate Professor, Chief of Services, William Feinbloom Vision Rehabilitation Center, Pennsylvania College of Optometry, Rick Thompson O.D., F.A.A.O., Developmental Optometrist and father of a daughter with albinism, and Jan Knuth M.S.W, 1st President of NOAH.
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