Low Vision Devices
Magnification is most often the key to helping people with Low Vision. Here is a brief description of some of the Low Vision magnification aids. Most of these tools have built in lighting to increase contrast while decreasing glare. The style and color of these lights is just as important as the strength of the lens.
Special Strong Reading Glasses
A Low Vision doctor is able to prescribe very strong reading glasses. The glasses must be used with proper task lighting (see LIGHTING section below), and the patient must learn to hold reading material EXACTLY where the glasses focus. Some resemble traditional spectacles, and some resemble the type of special glasses surgeons wear.
Stand magnifiers have a flashlight style handle. The magnifying lens area is encased in a box that allows the unit to rest directly on the page. This helps to eliminate fatigue in holding the magnifier.
These devices are available in the size of a large cell phone or as big as a personal computer. The small, portable versions are placed directly on the reading material. A miniature camera and lighting system on the bottom display the printed material on a small screen located on the upside of the unit. The size of the image can be increased or decreased as needed.
The larger versions have a tray where you can place your reading material. A small camera transmits the image from the tray to a large computer like screen. The image can be text from a book, newspaper, mail or even photographs. This machine can enlarge all the images dramatically.
Hand Held Magnifiers
These are just what they sound like; a magnifying glass with a small handle and light. These are small enough to carry in a purse or pocket and great for spot reading a menu, prices on items in stores, or brief reading of mail. However, they are not as convenient or comfortable as all previous options for extended periods of reading.
Besides needing magnification to see up close many Low Vision patients need magnification to help them see better at a distance. Here are a few of the devices that meet those needs.
Hand Held Telescopes
These are miniature versions of telescopes that can be held in one hand. They are approximately 1 to 2 inches in length. They are great at helping people read signs, see peoples faces, read the menu at a fast food restaurant, read the aisle signs in a grocery store, and even seeing the prices on the bottom or top shelves at a store.
Head Borne Telescopes
Telescopes can also be mounted into a pair of glasses for extended viewing sessions such as watching TV, seeing a play, graduation ceremony or attending a sporting event. Electronic versions also exist. However, walking or driving is not allowed.
Telescopes can also be mounted in a very high position in a pair of glasses. These are called bioptic telescopes. While not as convenient for extending viewing of TV or an event, walking is allowed. SOME states allow driving with bioptic telescopes BUT WITH VERY STRICT REQUIREMENTS.
A key ingredient to helping people with Low Vision see the best they can is lighting. Without the right lighting the correct magnification is often useless. Proper lighting was found to be so significant for Low Vision patients that many devices now incorporate lighting in the device itself. Yet there are tasks that may not involve the need for magnification devices, but do require proper lighting. Therefore, it is important for all patients to explore task lighting options and styles.
The most interesting thing about task lighting is that it differs for each person. No one can decide for someone else what the best type of lighting would be. The only way to determine this is to have the patient work with the various task lights and determine for themselves which helps the best.
The four categories of task lighting are:
This is basically your every day ordinary light bulb. When using incandescent lighting, the wattage of the bulb is important. Since glare is also a big factor in inhibiting vision, it is necessary to make sure the bulb is not too strong. Some people may need a 100 watts but many will not.
Fluorescent tubes or bulbs can be great for some people while others find this form of light far too disturbing. Again its up to the individual to tell you have well they see in each lighting situation.
Combination lights are lamps that contain an incandescent bulb that is surrounded by a fluorescent bulb. The lamp can be used just as a fluorescent light, just as an incandescent light, or as a combination of both.
The natural daylight bulb mimics the blue color of natural sunlight.
All task lights are available in either floor models or desk models but all have adjustable necks to control the placement of the light for each patient's specific tasks at hand. Remember no advertisement, friend or family member can decide what is the best lighting for someone with Low Vision. It is really as simple as having a person try to read under all four lighting examples and see which is the most comfortable.
Glare and Contrast
Almost all eye diseases create glare sensitivity. The extent of the glare sensitivity varies with environment. Outside on sunny days, outside on cloudy days, outside on snowy days, inside a grocery store, inside a dining hall are all examples of places that create various levels of glare sensitivity.
At the same time, however, it has been proven that those with low vision have reduced contrast. This means that images are not as bold as to those with good eyesight. Furthermore, sunglasses are usually only obtainable in gray or brown at regular eye doctors' offices or retail stores. For the low vision patient gray and brown may be too dark in many environments. Since vision is already reduced, often, dark sunglasses just make the vision duller.
Being able to safely walk, identify curbs, identify changes in the grades of carpeting, navigate strange environments, are very common complaints of Low Vision patients. Reduced vision, reduced contrast, and increased glare sensitivity, plus the addition of too dark of sunlenses which just worsen the situation, many times contribute more so to these complaints than the decrease in visual acuity.
Therefore, Low Vision researchers developed Contrast Enhancing Glare Filters. They were made to REDUCE GLARE WHILE ENHANCING CONTRAST.
The tints available are very different than regular sunglasses. They are plums, ambers, oranges, yellow, lighter than average shades of gray and brown. On the other hand, for those that have extreme glare issues and require no contrast enhancement, these filters are also available in extra dark colors. The filters are available in fitover styles, clip-on styles, or even with the patient's glasses prescription incorporated into them.
It is important for every patient with Low Vision to trial these filters to determine which is beneficial. As with lighting, filter choice is subjective and it is necessary for each patient to try the filters both inside and outside to determine which is best.
The goal of addressing glare sensitivity and contrast enhancement is to keep patients comfortable and safe. We want to reduce glare while still maximizing vision so as to maximize safety when mobile.