Types of Visual Impairment

This section includes information on some of the main causes of visual impairment today. It describes symptoms, causes, and treatments, provides information on prevalence, and suggests devices that can help people with these conditions maintain their independence.

Albinism. Albinism is a pigment deficiency causing several physical conditions, including vision problems. People with albinism often have low vision, including severe light and glare sensitivity. Albinism occurs in one person in 17,000 in the United States. Read more about albinism

Cataracts. Cataracts are the leading cause of preventable blindness worldwide. They are responsible for over 50% of the world’s blindness, over 20 million people. Cataracts are a clouding of the lens of the eye that causes light to be diffused as it enters the eye, impacting the clarity of the visual image. Most cataracts are a natural result of aging, but they can also be due to trauma to the eye. Read more about cataracts

Diabetic Retinopathy. Diabetic retinopathy is a complication of diabetes in which retinal blood vessels leak into the retina, causing macular edema (swelling). It is often caused by elevated blood sugar levels. Diabetic retinopathy causes over 8,000 cases of new blindness annually and is the primary cause of blindness for adults in the U.S. Read more about diabetic retinopathy

Glaucoma. Glaucoma is the most common eye disease, affecting more than 80 million people worldwide. Glaucoma involves damage to the optic nerve, usually caused by fluid build-up and increased pressure inside the eye. The result is a loss of peripheral vision, and often difficulty seeing in dim lighting. Read more about glaucoma

Age-related Macular Degeneration (AMD). Age-related Macular Degeneration (AMD) is the foremost cause of vision loss among Americans who are 60 and older. AMD involves damage to the macula in the back of the eye resulting in loss of central vision. Since central vision is used for many tasks, including reading, this can result in a loss of independence. Read more about AMD

Retinitis Pigmentosa (RP). Retinitis pigmentosa is an inherited eye disease found in over 100,000 people in the United States. It causes retinal degeneration and severe visual loss. It is a progressive disease that begins in childhood or adolescence, resulting in a loss of part of the visual field, along with reduced night vision. It often leads to severe visual impairment and sometimes total blindness. Read more about retinitis pigmentosa

Stargardt Disease. Stargardt disease is the most common form of inherited juvenile macular degeneration, occurring in one in every 8,000 to 10,000 people worldwide. It causes gradual loss of central vision. It usually develops during childhood or adolescence, resulting in a loss of the central part of the visual field. Read more about Stargardt disease


Albinism

Albinism is a relatively rare congenital disorder that occurs in about one person in every 17,000 in the United States. It is characterized by a lack of pigment in the hair, skin, and eyes. It is associated with vision problems, including low vision, nystagmus, and photophobia.

What is albinism? Albinism is a pigment deficiency that causes several physical conditions, the most prominent being lack of color in the hair, skin, and eyes. Albinism is genetic and occurs in all races, in fact, in all vertebrates. People with albinism often have low vision, including photophobia, a sensitivity to light and glare. They also often have nystagmus, a rapid irregular movement of the eyes from side to side.

What can be done if albinism is diagnosed? People who are born with albinism are advised to avoid sunlight, not only because they can get sunburn more easily, but also because their condition puts them at greater risk for certain types of skin cancer. Their visual impairment means they frequently need assistive technology to read and work.

What devices can help? Many people with albinism find that video magnifiers enable them to enjoy the activities of work, school, and their personal lives. By adjusting the contrast on the video magnifiers, they can use a magnified view without discomfort or fatigue. Freedom Scientific’s video magnifiers all have easy contrast adjustments.

  • TOPAZ Desktop Video Magnifiers allow you to read magazines and letters, view family photos, write checks, or engage in your favorite hobby, all in the comfort of your home or office.
  • RUBY Handheld Video Magnifiers can slip comfortably into a pocket or purse, giving you easy access to photos, letters, menus, prescription labels, and so much more, wherever you go.
  • ONYX Portable Video Magnifiers move from school to home to the office to help you see the board, read your assignments, take notes, do crafts, or to read, write, and view business presentations.
  • SAPPHIRE Handheld Video Magnifier magnifies bills, bank statements, and even three-dimensional items like food labels and pill bottles for continued independence.
  • MAGic Screen Magnification Software provides screen magnification and screen reading for low vision computer users.

Cataracts

Cataracts are the leading cause of preventable blindness worldwide. They are responsible for over 50% of the world’s blindness, over 20 million people. Cataracts are a clouding of the lens of the eye that causes light to be diffused as it enters the eye, impacting the clarity of the visual image. Most cataracts are a natural result of aging, but they can also be due to trauma to the eye.

What is a cataract? A cataract is a clouding of the lens of the eye. This causes light to be diffused as it enters the eye, impacting the clarity of the visual image. Cataracts usually develop quite slowly, so that people do not notice them until their vision is impacted. Common symptoms of cataracts are blurred vision, glare or light sensitivity, double vision, fading or yellowing of colors, poor night vision, and a need for increased light to read or perform close tasks.
While the most common cataracts are age-related, there are other types of cataracts that can result from diseases such as glaucoma, diabetes, or eye injury. Risk factors for cataracts include prolonged use of corticosteroids, excessive consumption of alcohol, smoking, and excessive exposure to sunlight. Usually cataracts develop in both eyes, but one may be worse than the other. Studies show an increased chance of cataract formation with unprotected exposure to ultraviolet (UV) radiation. For this reason, doctors recommend using sunglasses that block UV radiation while outside, even on cloudy days.

What can be done if cataracts are diagnosed? The main treatment for a cataract is surgery to replace the damaged lens. This surgery can usually be performed on an out-patient basis. Approximately one-half million people each year in the United States have cataract surgery, most of them over age 65.

What devices can help? Most cataracts are treatable with cataract surgery. If cataract surgery is not an option, it is important to be able to magnify text and objects so they are large enough to be visible outside the clouded central vision area. Freedom Scientific’s line of video magnifiers and screen magnification software can help with this.

  • TOPAZ Desktop Video Magnifiers allow you to read magazines and letters, view family photos, write checks, or engage in your favorite hobby, all in the comfort of your home or office.
  • RUBY Handheld Video Magnifiers can slip comfortably into a pocket or purse, giving you easy access to photos, letters, menus, prescription labels, and so much more, wherever you go.
  • ONYX Portable Video Magnifiers move from school to home to the office to help you see the board, read your assignments, take notes, do crafts, or to read, write, and view business presentations.
  • SAPPHIRE Handheld Video Magnifier magnifies bills, bank statements, and even three-dimensional items like food labels and pill bottles for continued independence.
  • MAGic Screen Magnification Software provides screen magnification and screen reading for low vision computer users.

Diabetic Retinopathy

Diabetic Retinopathy is a complication of diabetes in which retinal blood vessels leak into the retina, causing macular edema (swelling). It is often caused by elevated blood sugar levels. Diabetic retinopathy causes over 8,000 cases of new blindness annually and is the primary cause of blindness for adults in the U.S.

What is diabetic retinopathy? Diabetic retinopathy is a condition that affects people with diabetes, in which elevated blood sugar levels cause damage to the blood vessels in the back of the eye. Without the proper nutrients supplied by the blood, the retina cannot stay healthy. When blood vessels leak or break, it distorts the vision. Scarring can develop, and in some cases, a detached retina can occur. These all lead to worsening vision and sometimes blindness.
Anyone with type 1 or type 2 diabetes can develop diabetic retinopathy, although those with uncontrolled blood sugar levels are at higher risk. Symptoms of diabetic retinopathy often begin with blurring of the vision that generally worsens over time. As it develops, people can experience cloudy vision, loss of color vision, shadows or blind spots, or floaters. People with diabetic retinopathy often have trouble seeing at night. Careful control of diabetes and regular eye exams can delay the development of the disorder. Diabetic retinopathy often develops without pain and with minimal symptoms at first. Because it can be treated after an early diagnosis, it is critical to have an annual eye exam and to report any change in vision.

What can be done if diabetic retinopathy is diagnosed? The best treatment for diabetic retinopathy is to control the blood sugar levels. If the blood vessels in the back of the eye are leaking, laser surgery can often seal off the leaks that lead to macular edema. If the condition has progressed to the point that the blood vessels are leaking into the vitreous humor, a vitrectomy can be performed.

What devices can help? Many people who have lost some vision can use video magnifiers and screen magnification programs to retain independence. For those who have lost most or all their sight, screen reading software is recommended. Because many people with diabetes also experience lessened sensitivity in their fingers, they do not usually use Braille.

Glaucoma

Perhaps the most common eye disease in the world, glaucoma is a progressive condition that affects over 80 million people worldwide. People over 60 are at six times greater risk of developing glaucoma than the younger population, says the Glaucoma Research Foundation.

What is glaucoma? Glaucoma is characterized by damage to the optic nerve, resulting in unrelieved pressure inside the eye and fluid buildup. The cause is unknown but is probably genetic. Permanent impairment can range from loss of peripheral vision to severe vision loss. Individuals with glaucoma may experience increased frequency of headaches, blurred vision, halos around lights, difficulty seeing in dim lighting, and sometimes, a non-reactive pupil, pain, or even a swollen eye. However, the most common kind of glaucoma often has no apparent symptoms and no pain. When vision loss occurs, it usually happens slowly in the peripheral vision, so that people do not realize it is happening until the vision loss is quite advanced.

What can be done if glaucoma is diagnosed? Treatments commonly involve eye drops, beta blockers, oral medications, and/or surgery to relieve pressure. If left untreated, glaucoma can lead to blindness. While a cure is unknown, early diagnosis and treatment can save your eyesight to some extent.

What devices can help? Many people who lose their peripheral vision can benefit from a video magnifier. Because of the loss of peripheral vision, a large screen does not necessarily provide extra benefit. Often a small screen can be the most helpful. Therefore, handheld video magnifiers are often recommended.

  • RUBY Handheld Video Magnifiers can slip comfortably into a pocket or purse, giving you easy access to photos, letters, menus, prescription labels, and so much more, wherever you go.
  • TOPAZ Desktop Video Magnifiers, especially the 17” models, allow you to read magazines and letters, view family photos, write checks, or engage in your favorite hobby, all in the comfort of your home or office.

Age-related Macular Degeneration (AMD)

Age-related Macular Degeneration (AMD) is the foremost cause of vision loss among Americans who are 60 and older. AMD is not painful, so it is important to have your doctor perform a dilated eye exam regularly to catch AMD early. Warning signs of AMD include:

  • Lines that appear wavy or broken - even the edges of a square table or a book cover may appear distorted
  • Letters and numerals won’t come into focus
  • You see a dark spot in front of one or both eyes

What is AMD? Within the macula in the back of the eye is an area that contains the highest concentration of retinal cones, which produce the sharpest vision and are required to see details clearly. AMD results in damage to these cones. It is characterized by a worsening loss of central vision due to a growing "dark spot" seen directly in front of the eye, although peripheral vision may be clear. With Wet AMD, extra blood vessels form under the retina and grow and leak, causing visual impairment. Wet AMD is the most serious form of this eye disease and may occur suddenly. With Dry AMD, vision loss is slower. Dry AMD is the more common form, accounting for 90% of cases. Neither form of AMD causes complete blindness - you will always have some peripheral vision.

What can be done if AMD is diagnosed? Treatment can slow or stop the progression of AMD and vision loss. Treatments range from site injections to laser therapy. Several prescription drugs and therapies have shown promise to slightly improve visual acuity. However, nothing yet has been developed to reverse the effects of AMD.

What devices can help? Most people with AMD use aids to retain independence in their homes. Products include electronic magnifiers and devices that turn text into speech to read aloud mail, bills, books, and other printed materials. Freedom Scientific’s line of video magnifiers and screen magnification software can help.

  • TOPAZ Desktop Video Magnifiers allow you to read magazines and letters, view family photos, write checks, or engage in your favorite hobby, all in the comfort of your home or office.
  • RUBY Handheld Video Magnifiers can slip comfortably into a pocket or purse, giving you easy access to photos, letters, menus, prescription labels, and so much more, wherever you go.
  • ONYX Portable Video Magnifiers move from school to home to the office to help you see the board, read your assignments, take notes, do crafts, or to read, write, and view business presentations.
  • SAPPHIRE Handheld Video Magnifier magnifies bills, bank statements, and even three-dimensional items like food labels and pill bottles for continued independence.
  • MAGic Screen Magnification Software provides screen magnification and screen reading for low vision computer users.
  • SARA Scanning and Reading Appliances are self-contained appliances to read printed pages for people without computer experience who are blind or have low vision.

Retinitis Pigmentosa (RP)

Retinitis pigmentosa is a progressive eye disease found in over 100,000 people in the United States. It causes retinal degeneration and severe visual loss. RP causes a loss of part of the visual field, along with reduced night vision.

What is retinitis pigmentosa? Retinitis pigmentosa is an inherited eye disease, actually a group of inherited diseases. It often leads to severe visual impairment and sometimes total blindness. People with RP first develop noticeable symptoms in childhood or their teens. The first symptom most people notice is night blindness. The loss of vision is due to degeneration of the retina, specifically the rods and cones that serve as the light receptors. In most cases, the rods are affected first. Since rods are responsible for light and peripheral vision, most people find they need more light to see and perform tasks, and they cannot see well at night. When the cones are involved, the central vision and color perception are diminished. When retinitis pigmentosa occurs along with deafness, it is called Usher’s Syndrome.

What can be done if retinitis pigmentosa is diagnosed? There is no cure for retinitis pigmentosa, but some treatments exist to slow the progression of the disease. These mostly involve vitamin A supplements. Recent treatments include a retinal implant and retinal prosthesis. Recent research suggests that prolonged exposure to sunlight might increase the rate of vision loss, so people with RP are advised to wear sunglasses when outdoors.

What devices can help? For people with reduced vision due to retinitis pigmentosa, video magnifiers can help. They can provide both the magnification and the extra contrast and brightness to help with reading and other tasks. For those who have lost most or all their sight, screen reading software is recommended. Since retinitis pigmentosa usually begins in childhood, when people are still learning methods for reading, Braille is also a good solution.

Stargardt Disease

Stargardt disease is the most common form of inherited juvenile macular degeneration, occurring in one in every 8,000 to 10,000 people worldwide. It causes gradual loss of central vision. It usually develops during childhood or adolescence, resulting in a loss of the central part of the visual field.

What is Stargardt disease? Stargardt disease is an inherited form of macular degeneration that first appears in childhood or adolescence. It is characterized by progressive vision loss beginning in the macula, the central part of the retina where light falls and visual acuity and color vision are greatest. Symptoms include blurred or wavy vision, blind spots, impaired color vision, and difficulty seeing in low light situations. People with Stargardt disease are usually sensitive to glare.

What can be done if Stargardt disease is diagnosed? There is no cure for Stargardt disease, and there are no treatments.

What devices can help? Since the symptoms are underlying physiology of Stargardt disease are similar to those for other types of macular degeneration, people can usually benefit from the same devices as used for age-related macular degeneration (AMD). These help people retain independence in their homes, school, and jobs. Products include electronic magnifiers and devices that turn text into speech to read aloud mail, bills, books, and other printed materials. Freedom Scientific’s line of video magnifiers and screen magnification software can help.

  • TOPAZ Desktop Video Magnifiers allow you to read magazines and letters, view family photos, write checks, or engage in your favorite hobby, all in the comfort of your home or office.
  • RUBY Handheld Video Magnifiers can slip comfortably into a pocket or purse, giving you easy access to photos, letters, menus, prescription labels, and so much more, wherever you go.
  • ONYX Portable Video Magnifiers move from school to home to the office to help you see the board, read your assignments, take notes, do crafts, or to read, write, and view business presentations.
  • SAPPHIRE Handheld Video Magnifier magnifies bills, bank statements, and even three-dimensional items like food labels and pill bottles for continued independence.
  • MAGic Screen Magnification Software provides screen magnification and screen reading for low vision computer users.