Posts Tagged ‘macula’

Learn About Low Vision

February 10th, 2019

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.

Low Vision Chart

  • 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.

There are also many low vision aids that can help you see when doing your everyday activities. These includes a variety of optical magnifiers, including those that attach to your glasses, those that are handheld and those that stand on their own hands-free.

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!

Aiming at AMD

March 20th, 2018

If you’re a Baby Boomer, like me, now’s the time to get wise about a dangerous threat to your eyesight. It’s age-related macular degeneration, or AMD, and it’s one of the leading causes of vision loss in people over 50. To get you started learning more, here are a few realities about this insidious eye disease.

For one thing, AMD is everywhere. The US Centers for Disease Control and Prevention estimate that 1.8 million Americans currently have AMD and another 7.3 million are at substantial risk for vision loss from the disorder. And as we Baby Boomers continue to age, the number with AMD is expected to rise significantly, to an estimated 6.3 million by 2030.

AMD is a disease that affects the macula, the center portion of the retina. The retina is the sensitive area in the back of the eyeball responsible for capturing light that enters the eye and turning it into nerve impulses sent to the brain by the optic nerve. The brain translates the impulses into images.

The macula is responsible for the straight-ahead central vision that allows us to see fine detail. This central vision provided by the macula enables us to distinguish faces, read, write and do close-up work like sewing and baiting a fishing hook.

There are two forms of AMD, the dry form and the wet form. About 80 percent of people with AMD have the dry form, which occurs when the tissue of the macula gets thinner and deteriorates with age. With the dry form of AMD, small clumps of protein, called drusen, begin to grow, and you may start to slowly lose vision.

The wet form of AMD, which is much less common, involves the growth of abnormal blood vessels under the retina. In time, these abnormal vessels can leak blood and other fluids. The leaked fluids can damage the macula and lead to loss of vision, which typically occurs more quickly than with dry AMD. The dry form can progress into the wet form over time.

The key to saving your vision is early detection and intervention, but you’ve got to watch out. AMD is tricky. It can be hard to detect initially because it doesn’t typically have noticeable symptoms in its early stages, outside of the presence of drusen. That’s why it’s important to see your eye doctor regularly so he or she can examine your retinas closely to look for drusen and any other signs AMD is developing.

As AMD progresses, however, you may notice a blurry area in the center of your vision that may evolve into an empty spot. That empty area may be apparent when reading a page of type, like a book or newspaper. In addition, straight lines may look wavy, and colors might not be as sharp. Objects in your view may also appear blurry or distorted. If these symptoms occur, see your eye doctor right away.

Currently, there is no treatment for dry AMD, especially in its early stages. However, research has shown that this disease is less prevalent in people who exercise regularly, eat a healthy diet with lots of green leafy vegetables and fish, and don’t smoke. Eye professionals believe these healthy behaviors may also help people with dry AMD keep their vision longer.

The belief about a healthy diet was bolstered by two research trials called the Age-Related Eye Disease Studies (AREDS and AREDS2). During these trials, scientists at the National Eye Institute studied the effects of vitamin and mineral supplementation on AMD. They determined that taking a specific formulation of vitamins and minerals slowed the progression of AMD in people who had intermediate and late disease. AREDS2 supplement therapy is now routine.

For people with wet AMD, there are several treatments available to destroy the abnormal blood vessels growing underneath the retina and halt the progression of the disease. These include laser surgery and photodynamic therapy, both of which use lasers to close the abnormal vessels and slow the loss of vision.

More commonly, though, are monthly injections into the eye to slow the progression of wet AMD. With wet AMD, high levels of a protein called vascular endothelial growth factor (VEGF) are released into the eyes. VEGF promotes the growth of the new, abnormal blood vessels. During this treatment, anti-VEGF medications are injected into the eye, which blocks the new vessels growth.

None of these treatments for AMD are cures, and they can’t restore vision that is already lost. But they can help slow additional vision loss. If you’re a Baby Boomer, be sure to see your eye doctor regularly to check for signs AMD is developing. Remember, early action can limit loss and save your remaining vision.

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