Any departure from normal corrected vision is considered a visual impairment. Hazy vision, light sensitivity, night blindness, central or peripheral vision loss, or just a lack of contrast sensitivity are all possible symptoms. The key aspect is that it is a visual impairment that cannot be rectified.
What are the causes of visual impairment?
Common causes of visual impairment include the following.
- Cataracts which make up about 33% of all vision loss. Cataracts can be easily removed to correct the issue. Globally cataracts are probably the most common vision impairment due to the lack of medical facilities and access to cataract surgeons.
- Glaucoma is another common cause of permanent vision loss and affects peripheral vision. Glaucoma is a very slow insidious disease and can take decades for vision loss to occur especially with treatment. It is responsible for about 2% of all visual impairments globally.
- Uncorrected refractive errors are probably responsible for most visual impairments, these include myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. These aren’t truly visual impairments as per the definition because they can be corrected with glasses or contact lenses. However, while uncorrected for whatever reason they can be just as visually devastating as the diseases that cause permanent vision loss.
- Macular degeneration causes central vision loss which can lead to central blurred vision or in more severe cases complete blind spots in the center of your vision which makes it difficult to read, write or even just see faces clearly. It can cause enough vision loss that you may not be able to see street signs well enough to continue driving. Although this disease affects only a small part of the visual field and retina it has devastating effects on usable vision. Macular degeneration usually starts as a dry version and with time can progress to a much more progressive form called wet macular degeneration.
- Less common causes of visual impairment include night blindness which is often caused by a disease called retinitis pigmentosa which affects the peripheral rods of the retina which are responsible for movement in low light levels. Corneal opacities or scars are also permanent reasons for vision loss, they can block light and or distort the light as it passes through the cornea.
- Diabetic retinopathy is a very common cause of vision loss. unfortunately, more and more American’s are being diagnosed with diabetes and with time this can lead to retinopathy if not followed closely. Diabetic retinopathy can lead to vision loss throughout the retina and visual field. It’s a disease that affects the small blood vessels of the eye. It can have severe effects on the macula as like macular degeneration but can also lead to peripheral loss due to bleeding but also due to causing secondary glaucoma. In severe cases could even lead to retinal detachments.
- Amblyopia is a visual impairment that mostly occurs in children and can persist into adulthood especially if left untreated. Amblyopia can be caused by many different reasons, including a lazy eye (strabismus) lenticular opacity (cataracts), and uncorrected refractive errors. This happens a lot with high amounts of uncorrected astigmatism or where one eye has considerably more correction than the other causing one eye to be suppressed. Amblyopia is a condition where the brain cells in the visual cortex are underutilized or suppressed in situations where the vision would be worse if the brain cells aren’t suppressed. For example, in the case of an eye turn, if suppression doesn’t take place the patient will see double vision. Once the suppression occurs for a long period of time the brain cells in the visual cortex (where vision occurs) will atrophy or become less efficient due to lack of use.
Who does visual impairment affect?
Due to so many conditions that can cause visual impairments the ages and demographics varies greatly. Amblyopia is a condition usually found in kids, cataracts, glaucoma, and macular degeneration all tend to affect elderly people. Genetic diseases like corneal dystrophies or retinitis pigmentosa usually cause vision impairment in early adulthood. Diabetic retinopathy tends to occur between the ages of 45-64. Macular degeneration usually affects Caucasians, Glaucoma and diabetes usually affects black more prevalently.
Is visually impaired the same as legally blind and low vision?
Those that are visually impaired can be legally blind however the definition of visually impaired and low vision is much more loosely defined. Since it can be anyone who has less than perfect vision. Legally blind is much more strictly defined as best corrected vision that is 20/200 or less or someone that has less than 20 degrees of visual field. Visually impaired and low vision are synonymous with each other. Both imply a decreased visual ability but is more about function than and actual measurement of actual vision. In other words, are you able to see to do the things you need to be able to do daily with normal correction such as glasses? If the answer is no, then you may be visually impaired or have low vision. If your best corrected vision is 20/200 or less then you are visually impaired, have low vision and you’re legally blind, if due to the decreased visual acuity that you can’t do and see all the things you need to be able to do.
Is Near/ farsighted the same as visually impaired and low vision?
Near and far-sighted are terms relating to refractive error. For most people, their refractive error can be corrected by glasses or contact lenses. If you are unable for whatever reason to have your refractive error corrected, you would be considered visually impaired. However, if you are able to do your normal daily activities and have the ability to be corrected you wouldn’t have low vision.
How are the visually impaired treated?
With so many different causes of visual impairment, there are obviously a multitude of different treatments. the easiest treatment for the most common vision impairment which is uncorrected refractive errors is glasses and or contacts lenses. The treatment of cataracts has come so far. The surgery literally takes about 5 minutes, 10 minutes if it’s a complicated case. Amblyopia is also treated with glasses in many cases or vision therapy if there Is a lazy eye or long-standing suppression.
Glaucoma needs to be followed by a glaucoma specialist on a fairly tight regimen. The disease is usually treated with drops to control the pressure of the eyes. If at some point the pressures are no longer controlled by the drops then surgery will be indicated. Macular degeneration and diabetic retinopathy are usually followed by a retinal specialist up to the point when scarring no longer warrants treatment.
All of these visual impairments along with Inherited diseases like corneal dystrophies and retinitis pigmentosa can all be treated by a low vision specialist when no other medical treatment can improve the vision.
Low vision specialists help maximize the remaining vision of someone that is visually impaired. They prescribe devices such as bioptic telescope glasses to help spot street signs when driving or microscope glasses to assist in reading and writing. Many new electronic visual aids can also assist in daily activities such as working on the computer or just playing cards with friends.
How do I prevent becoming visually impaired?
Being visually impaired doesn’t mean that you are blind, and, in most cases, many are not a serious problem. Staying on top of your ocular health like any other health condition is the best way to prevent problems down the road. See an optometrist or ophthalmologist regularly and more often if you are noticing a visual impairment starting. Take care of your overall health, maintain healthy body weight, and eat a healthy balanced diet. Have regular health checkups with your doctor. Don’t smoke! Exercise regularly. Wear safety eyewear when in dangerous environments and wear sunglasses when out in the sun. Follow your eye doctors’ recommendations for taking care of your eyes and contact lenses if you wear them.
Who is at most risk for becoming visually impaired?
Diabetes is the most common cause of visual impairment in the United States. Therefore, those at risk for developing diabetes or those already dealing with the disease are most likely at the highest risk for becoming visually impaired.
Who should I see for my visual impairment?
The impairment cause will dictate who you may need to see for the condition. If it is a medical condition that needs to be treated then the appropriate specialist should be seen such as a glaucoma specialist, cataract surgeon, or retinal specialist. If the condition can no longer be treated medically then a low vision specialist or occupational therapist specializing in low vision should be see.
What are the myths about visual impairment?
Myth 1: Visually impaired people are all legally blind.
Fact: Most visually impaired people aren’t even close to legally blind. Most have minor impairments that are easily overcome by proper treatment, devices, and techniques.
Myth 2: If I’m visually impaired I can no longer drive.
Fact: Many that are visually impaired are still able to drive a car under normal circumstances depending on the severity of their impairment. In more severe cases of low vision where the acuity or peripheral vision is decreased beyond normal driving regulations then it may be required to use a device like a bioptic which is a miniaturized telescope mounted on the top of a pair of glasses. About 46 out of the 50 states allow these to be used.
Myth 3: If I have low vision, I can no longer live by myself.
Fact: People with low vision have such a huge range of visual ability and most fall within the range that easily allows them to function on their own, especially when trained to use low vision devices and techniques.
Myth 4: Being visually impaired means, I’m handicapped.
Fact: Although some with visual disabilities are handicapped and can’t do certain activities. Most can learn to adapt and use devices and techniques to overcome most difficulties.
Myth 5: Having vision loss in one eye means I have low vision.
Fact: We use both eyes to function in our daily lives. If the vision in the good eye allows you to do everything you need to do without difficulty, then you don’t have low vision. You have a visual impairment in one eye, however.
Myth 6: Without my glasses on I can’t see the big E therefore I’m legally blind.
Fact: The term legally blind means with correction. If you can see 20/200 with your correction you are not legally blind.
Myth 7: My retinal specialist says that there is nothing more that he can do for my visual impairment since I can no longer be treated medically. Therefore, nothing more can be done for me and my vision.
Fact: Although nothing more may be able to be done for the physical structures of your eyes. A visit to a low vision specialist can greatly improve the usable vision that you have left.
What steps can you take when you are visually impaired?
Depending on the cause and severity of your visual impairment, you should have a team of doctors and resources in the community to help you to treat, cope, and adapt to whatever visual condition you may have. See your medical eye doctors as recommended. Schedule to see a low vision specialist and or occupational therapist if needed to help you maximize your vision that you do have.