Do you worry about your vision? Many of us do. Vision loss is a common condition in the United States. It’s estimated that 25 million Americans are blind or visually impaired. One in 28 Americans ages 40 and older have low vision. Since low vision is so prevalent, I thought we ought to learn more about it.
First of all, let’s define low vision. It’s a significant visual impairment that can’t be corrected by any type of prescription lenses, or by medication or surgery. Low vision can make it difficult to perform your daily activities, as well as to read, use a computer, drive and watch TV. This can make you feel cut off from the world around you.
Low vision can also affect your mobility. It can interfere with your ability to get around independently. When mobility and communication are hampered, it can lead to feelings of anxiety and depression, and quality of life can be negatively affected in some people.
Eye disorders and injuries to the eye are the primary causes of low vision. These include diseases like macular degeneration, glaucoma and diabetic retinopathy, and genetic conditions like retinitis pigmentosa, as well as conditions like cataracts and traumatic brain injury, including head injuries, brain tumors and stroke.
There are a few common types of low vision. The first is the loss of central vision in which there’s a blur or blind spot in the middle of your vision, but your peripheral, or side, vision remains intact. This can occur with macular degeneration because the macula is responsible for central vision.
20/30 to 20/60, this is considered mild vision loss, or near-normal vision.
20/70 to 20/160, this is considered moderate visual impairment, or moderate low vision.
20/200 to 20/400, this is considered severe visual impairment, or severe low vision.
20/500 to 20/1,000, this is considered profound visual impairment, or profound low vision.
less than 20/1,000, this is considered near-total visual impairment, or near-total blindness.
no light perception, this is considered total visual impairment, or total blindness.
Other types of low vision include loss of peripheral vision. With this, you won’t be able to distinguish anything at one or both sides, or anything directly above and/or below eye level. Loss of peripheral vision can happen with glaucoma and stroke. With blurred vision, both your near and far vision is out of focus. Cataracts can cause this.
There’s also a condition called generalized haze, when it seems like there’s a film covering everything you look at. Extreme light sensitivity is another common type of low vision. This is when regular amounts of light feel overwhelming. With night blindness, another type, you cannot see outside at night or in dimly-lit places indoors. Various eye disorders can cause these conditions.
Anyone can be affected by low vision, but it’s more common as we get older. That’s true, in part, because conditions that often cause low vision, such as macular degeneration and glaucoma, most commonly develop as people age.
Low vision is more frequently seen in people over age 45 and even more frequently seen in people over age 75. In fact, one in six adults over age 45 has low vision, and one in four adults over 75 has it.
The best way to catch and control the diseases and conditions that lead to low vision is by having regular eye exams by an eye care specialist. But if you notice any changes in your vision, contact your eye doctor right away.
Your eye doctor will perform a complete eye exam to diagnose low vision, including tests designed to check your vision and look for eye diseases. Your doctor will test your eyes for visual acuity or how well you see. He or she may use different instruments and lights when testing your vision.
If your eye doctor diagnoses low vision, he or she may refer you to a low vision specialist. A low vision specialist will help you learn new ways to use your remaining vision, modify your home and teach you how to use devices to aid your vision. Visual rehabilitation is part of this process.
Visual rehabilitation begins by recognizing the challenges of vision loss and making adjustments to maximize what vision you have left. It’s a process of learning how to do tasks, such as reading and writing, in news ways.
For example, if you have a blind spot, you may be asked to imagine the object you want to see is in the center of a large clock. You’ll be told to move your eyes along the clock numbers and note when you see the object most clearly. The doctor will tell you to use the same viewing direction when you look at other objects to see them as clearly as possible.
Telescopes can help you see things that are far away. They can be handheld or attached to your glasses. Non-optical aids that are available include everyday devices that talk. Some examples are watches, timers and blood sugar monitors that have an audio component.
There are also electronic devices such as video magnifies in portable and desktop formats. These devices combine a camera and a screen to make objects, like printed pages, forms and pictures, look larger.
Also helpful to those with low vision are audio books and electronic books that allow you to increase word size and contrast. The latest technology in smartphones, tablets and computers can read aloud or magnify what’s on the screen.
Low vision may be preventable in people with diabetes if they maintain healthy blood glucose levels. The best way to prevent the progression of low vision is by getting your eyes examined regularly so your doctor can catch and manage the eye disorders that can contribute to low vision. Do your eyes a favor, keep an eye on them!