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Low Vision and Low Vision Aids

Normal vision is the ability to see comfortably what is around us, whether far away or near, with or without glasses. This is vision around 6/6 (20/20). Almost everyone can continue to manage their activities when changes in vision are small.

Normal vision is known as "6/6"(20/20) because the eye being tested can see an object at 6 metres or 20 feet. If you have 6/12 (20/40) vision, this means you can see at 6 metres or 20 feet what a person with good vision can see at 6 metres or 60 feet. As changes in vision become larger, most people experience more and more difficulty in their efforts to continue their usual visual activities, even with the best possible glasses or contact lenses. If this is a change in vision between 6/19 and less than 6/60 (20/60 and 20/190) it is called being partially sighted or having low vision. If the change in vision is to 6/60 (20/200) or worse, some vision may be retained but will be classified as blind.​

Low vision can result from a variety of diseases, disorders, and injuries that affect the eye. Many people with low vision have age-related macular degeneration, cataract, glaucoma, or diabetic retinopathy. Age-related macular degeneration accounts for almost 45 percent of all cases of low vision.

Low vision can occur at any age, but by far the greatest number of people who are partially sighted are the elderly. Low vision is most often due to a change in central vision. Occasionally it is associated with loss of side (peripheral) vision when it is close to centre. In a few cases it is associated with loss of colour vision or difficulty adapting to changes in brightness within the field of vision.

Low vision devices can help you make the most of your vision so that you can perform everyday tasks more easily and with less frustration. There are several different categories of low vision devices: optical devices, non-optical devices, and electronic magnifiers and magnifying systems. Low vision devices are task-specific, designed for close-up visual tasks or distance viewing. You may require several different devices to accomplish different tasks, depending upon your eye condition and your everyday living needs.

Low Vision Optical Devices

Low vision optical devices include a variety of helpful visual aids, including stand and hand-held magnifiers, strong magnifying reading glasses, loupes, and small telescopes. Because these devices can provide greatly increased magnification powers and prescription strengths, along with higher-quality optics (i.e. the way the lens bends or refracts light), they are different from regular glasses and magnifiers that you can buy in a local store or online. Most often they require training to help you use them effectively.

Low Vision Non-Optical Devices

Low vision non-optical devices can include adaptations such as reading stands, supplemental lighting, absorptive (or glare control) sunglasses, typoscopes, and tactile locator dots. They can be used in combination with low vision optical devices and can help with reading, organizing, labeling, and a variety of everyday tasks.

hand held telescope


Electronic Magnifying Systems

Electronic magnifying systems come in many different varieties and sizes, depending upon the task or activity you want, or need, to do. Some have a camera system that displays a magnified image on a monitor, which can be helpful for reading mail, books, and magazines, while others are hand-held, portable, and can be taken to the supermarket to read labels and coupons, or to restaurants to read menus.


Source: RNIB