What Are the Most Common Non-Optical Devices?
Low vision non-optical devices can include adaptations such as supplemental lighting, absorptive sunlenses, and colored acetate filters. They are usually recommended as part of a low vision examination and can be used in combination with magnifiers and other low vision optical devices that can help with reading.
The most common low vision non-optical devices include:
Flexible-Arm Task Lamps
Because proper lighting is critical for good vision, flexible-arm task lamps are the leading non-optical devices for many people.
The advantages of flexibe-arm task lamps are:
- Easily obtained
- Can be adjusted to a variety of tasks and settings.
The disadvantages of flexible-arm task lamps are:
- You will need to experiment with position and intensities in order to achieve the best results.
- Flexible-arm task lamps produce heat — use precautions when positioning lamps close to your body, curtains, or furniture.
- Most lamps are not as portable as low vision optical devices.
Full Spectrum Light Bulbs
Full spectrum light bulbs provide the full range of colors found in sunlight, but are more expensive than regular bulbs. They can be purchased at any lighting store or ordered through catalogs. If you use a full spectrum bulb for long periods of time, you may need to take precautions with sunscreen, just as you would if you were outdoors in the sunlight.
Electronic Video Magnifiers
An an electronic video magnifier is equipment for reading that consists of a stand-mounted or hand-held video camera that displays a magnified image on a video monitor, television screen, or computer monitor. It enables some individuals with low vision to read books, newspapers, magazines, and other print materials, such as medication labels, and to view photographs, charts, and illustrations.
Electronic video monitors are available in a variety of styles and magnification. They also tend to be expensive. Before you purchase one, consider having a low vision examination with either an optometrist or ophthalmologist, who has had additional training in low vision, and discuss your desire to use an electronic video magnifier.
Try to find an agency or location in which you can have hands-on experience with a variety of machines before purchasing one. It can take a little while to learn how to use an video magnifier effectively; certain controls will likely be easier for you to use than others.
Take your time and check the particular features that work best for you. Some doctors, low vision clinics, and vision rehabilitation agencies offer loaner programs and/or resale of older but perfectly good machines, which could reduce the purchase price substantially.
Absorptive lenses are special wraparound sunglasses that filter out ultraviolet and infrared light. The range of tints includes yellows, plums, green, blues, and browns.
- They are helpful for individuals who are sensitive to bright light and glare.
- They reduce glare and increase contrast.
- They are inexpensive and easily obtained.
- They can be fitted over regular glasses or tints can be added to prescription lenses.
- They are available in a variety of colors and tints, in either plastic or glass.
Colored Acetate Sheets
When placed on the page, a translucent acetate sheet - especially yellow or marigold - can enhance contrast between the print and background, making words and letters appear darker and easier to read:
Examples of acetate filters
Examples of yellow overlay sheets
Using Optical and Non-Optical Low Vision Devices
Before any optical or non-optical device can be effective and comfortable, you will need to:
- Be motivated to use the device for specific tasks
- Be confident that the device has been appropriately prescribed
- Know how to maximize the use of the device
- Know its potential and limitations
- Supplement your use of the device with appropriate lighting
To achieve the best results from the use of any low vision optical device, lighting from a flexible-arm task lamp can often prove to be essential.
It's also important to realize that it often takes time, patience, and much encouragement and support to learn how to use low vision optical devices effectively and efficiently.
Friends and family can play an important role in encouraging you to be patient, to experiment with lighting positions and intensities, and to practice under different lighting conditions, such as the time of day and indoor/outdoor situations.
- A Progress Update: the OrCam Wearable Visual System
by Maureen Duffy on 12/4/2014