What is Low Vision?
Low vision is a loss of eyesight that makes everyday tasks difficult. A person with low vision may find it difficult or impossible to accomplish activities such as reading, writing, shopping, watching television, driving a car or recognizing faces. When vision cannot be improved with regular eyeglasses, medicine or surgery, people with low vision need help to learn how to make the most of their remaining sight and keep their independence. Losing vision does not mean giving up your activities, but it does mean finding new ways of doing them.
- Patterns of vision and vision loss
- Central vision: This is the detailed vision we use when we look directly at something. Macular degeneration (AMD) affects central vision. Diabetic retinopathy can affect central or peripheral vision.
- Peripheral vision: This is the less detailed vision we use to see everything around the edges. Glaucoma affects peripheral vision first. Strokes can affect one side of the peripheral vision.
- Contrast sensitivity: This is the ability to distinguish between objects of similar tones like milk in a white cup or to distinguish facial features. All eye problems can decrease contrast sensitivity.
- Depth perception: This is the ability to judge the position of objects. New vision loss in one eye can affect depth perception, such as the height of a step.
- Visual processing: The lens in our eye focuses light rays onto our retina. The retina converts these light rays into signals that are sent through the optic nerve to our brain, where they are interpreted as the images we see. A problem with any of these processes affects our vision in various ways.
The experience of vision loss
It is always a shock to learn that your vision loss cannot be reversed. It is important to recognize the anger and frustration you may feel, to get help working through these feelings, and to apply the strategies of vision rehabilitation to stay active, including using low vision aids and low vision rehabilitation. If you have low vision, taking care of yourself and staying active will help you avoid depression (which may appear as fatigue or lack of interest). If you are depressed, seek treatment and counseling. A good low vision support group can help you recognize that your value to yourself and others does not depend on your vision, and that you are worth the effort it takes to make the most of the vision you have.
What Causes Low Vision?
Low vision can be caused by eye diseases, such as macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa. It can also be caused by eye injuries. These conditions can occur at any age but are more common in older people. However, normal aging of the eye does not lead to low vision. Low vision may also result from cancer of the eye, albinism or a brain injury. If you have these disorders or are at risk for them, you are also at greater risk for low vision. Regular medical eye exams by an ophthalmologist are important to diagnose eye diseases, treat those conditions that can be helped, and start the process of vision rehabilitation for people with low vision.
Low Vision Symptoms
With low vision, you cannot see well enough to do everyday tasks — even with regular glasses, contact lenses, medicine or surgery. There are many signs of vision loss: finding it difficult or impossible to read, write, shop, watch television, drive a car or recognize faces. It may be difficult to set dials or manage glare. With low vision, you might have trouble picking out and matching the color of your clothes. The lights may seem dimmer than they used to, making work or household chores more difficult. The most common types of low vision include loss of central vision, loss of peripheral (side) vision, night blindness, blurred vision and hazy vision.
The phantom visions of Charles Bonnet syndrome
About 20 to 30 percent of people with vision loss see lifelike images they know are not real. This is called Charles Bonnet syndrome (CBS). It is important to understand that this syndrome is not a loss of mental capacity, but just part of vision loss for some. It is helpful to think of these images as being produced by the brain to replace the absence of images produced by the damaged eye.
Low Vision Diagnosis and TreatmentTo help diagnose low vision, the complete eye exam usually begins with questions about your medical history and any vision problems you might be experiencing. It also involves a number of tests designed to evaluate your vision and check for eye diseases. Your doctor may use a variety of instruments, aim bright lights directly at your eyes, and ask you to look through an array of lenses.
Next, your doctor will check your eyes with a light to see whether the outside of your eyes are functioning correctly and whether there are any signs of injury or disease. Your eyes will also be tested for visual acuity, or how well you see.
Low vision is a permanent loss of vision that cannot be improved with eyeglasses, medicine or surgery. If you have been diagnosed with low vision, there is no treatment that will give you back your vision. Instead, you will need to learn new ways to use your remaining vision to complete everyday tasks and maintain your quality of life.
Remember, low vision is not a normal symptom of aging. Your ophthalmologist can tell the difference between normal changes in an aging eye and those caused by eye diseases. If you have noticed changes in your vision, see your eye doctor right away.
Low Vision Aids and Low Vision RehabilitationLosing vision does not mean giving up your activities, but it does mean applying new ways of doing them. Is it difficult to read newspapers and price tags, set dials, or manage glare? There are numerous tools, techniques and resources for people with low vision, including low vision aids and low vision rehabilitation.
If your family member or friend has vision loss, he or she needs to be empowered to do as much as possible independently. Recognize the challenges of vision loss, but don’t take over their tasks. Instead, help identify the adjustments they need to make to maximize their independence.
Make the most of your remaining visionFind and use your “next-best spot": scotomas and PRLs When the center of your vision is obscured by a blind spot (scotoma), it is helpful to locate your "next best spot" (the Preferred Retinal Locus or PRL). To find your PRL, imagine that the object you want to see is in the center of a large clock face. Move your eyes along the clock numbers and notice when you see the center object most clearly. Use that same viewing direction for other objects.
Low vision aidsThere are numerous tips and devices to help you remain independent with low vision, including making things brighter and bigger, reorganizing your home or work environment, using audio books and devices and more.
Make things brighterImprove lighting. Use a gooseneck lamp directed onto your task. Carry a penlight. Reduce glare. Indoors, cover wood tables and shiny counters; wear yellow clip-on or fitover glasses. Outdoors, try dark yellow or amber glasses. Visors can be useful indoors or out. Increase contrast. Use a black ink gel or felt pen, not a ballpoint. Draw a dark line where you need to sign. Use a white cup for coffee, for example.
Make things biggerMove closer. Sit close to the TV, and up front at performances. Enlarge. Get large checks, large-print playing cards, bingo cards, crosswords, phone dials, TV remotes, calendars, keyboards, and books. Magnify. Low vision magnifiers come in many powers and types, suited to different people and different tasks: hand-held for price tags and menus, stands and video magnifiers (CCTVs or closed circuit TVs) for sentences, magnifying computer mouse. Organize Designate spots for the items in your refrigerator, and for your keys and wallet. Minimize clutter. Separate black clothes from blue.
Label things clearlyMark thermostats and dials with high contrast markers from a fabric store; label medications with markers or rubber bands; safety-pin the labels of similar-colored clothing.
Substitute ears for eyesUse electronic books, e-book readers and audio books. Talking watches, clocks, calculators, glucometers, and computers are also helpful. Use reading services.
ParticipateDon’t isolate yourself. Keep your social group, volunteer job, or golf game. It might require lighting, large print cards, a magnifier, a ride, or someone to watch your golf ball. Ask for the help you need. There is nothing independent about staying home to avoid asking for help.
DrivingIf you are able to drive, pick your times and map routes carefully. Consider yellow or amber sunglasses for glare. But be prepared to consider whether or not driving is a good idea. Ask yourself the following questions: Do cars appear unexpectedly? Do drivers honk at you? Are you having fender-benders? If “yes,” consider transportation alternatives. Hire a driver or arrange for a taxi. Share your car or buy gas for a friend who drives. Use senior and public transit systems. Try a three-wheel bike or battery-powered scooter at walking speed. Walk if you are able. The future will offer even more solutions.
Newer technology for low vision aidsWhile low vision devices like closed-circuit TV (CCTV) magnifiers have long been the standard in assistive technology, advances in consumer electronics are also improving quality of life for people with low vision.
E-readersThe Kindle® , the iPad® and other electronic readers (e-readers) are portable and more affordable alternatives to the CCTV. E-readers can be used on-the-go and can be one-tenth the price of CCTVs in some instances. The Kindle and the iPad allow the user to adjust the font size and contrast settings of the display. Both have text-to-speech functionality and can read aloud to the user. It's important to keep in mind that e-readers don't offer the same level of magnification as CCTVs and will not meet the needs of everyone with low vision. For example, be sure the display of the device works for your contrast sensitivity. Not all e-readers offer reversed-polarity (white letters on black background) displays, which reduce glare and may be easier to read for some people.
Smartphones and tabletsBoth Apple- and Android-based smartphones and tablets offer a range of apps and built-in functions to help people with low vision:
MagnifyiRead, iLoupe, and Magnify use your device's camera and light source to magnify and illuminate text. While these apps won't match the power of a CCTV, they're portable, less-expensive alternatives for those who need some level of magnification. Browse your Apple or Android app store for pricing and availability.
Smart moneyEyeNote is a free app available for Apple products that scans and identifies the denomination of U.S. paper money by reading aloud or emitting an ascending number of beeps or pulsed vibrations for each bill.
SightBookThis free app digitally communicates your vision changes to your ophthalmologist by measuring your visual function with a set of near vision tests. Significant changes in vision are recorded and then sent wirelessly to your doctor. The app is free and available on iTunes. Visit www.digisight.net for more information to share with your Eye M.D.
MapQuestAvailable for Apple and Android phones, the MapQuest app provides voice-guided directions and tells the driver when to turn. If you make a wrong turn, MapQuest will re-route you automatically.
Voice interfaceSiri, the voice recognition system on the iPhone 4S, can be a helpful low-vision aid as it allows the user to check the weather, email, or their calendar without having to visually navigate a series of icons. Android-based phones also have voice-recognition capability allowing the user to dictate texts or emails without having to type.
These new advances in consumer technology are not a cure-all for those with low vision. Many people will need additional devices and aids along with the assistance of their vision rehabilitation specialist to achieve best possible vision. However, for many people, these digital devices and apps offer more options for portable, lower-cost low vision aids.
Low vision rehabilitationIf you have low vision, you can greatly improve your quality of life through vision rehabilitation. Low vision rehabilitation teaches you how to use your remaining vision more effectively.
When checking out low vision rehabilitation services near you, ask if services include:
- A low vision evaluation by an ophthalmologist or optometrist.
- Prescription for devices: Are some devices loaned before purchase, or returnable?
- Rehabilitation training: reading, writing, shopping, cooking, lighting and glare control?
- Home assessment?
- Mobility services?
- Resources and support groups?
- Are services free, billed to Medicare or other insurances? If not, what is the charge?
(Note: Medicare covers most services, but not devices.)
If you would like more information about this procedure you can make an appointment or contact the office for additional information.