Low vision is a visual impairment that cannot be corrected with standard eyeglasses, contact lenses, medication, or surgery. With low vision, activities like reading, shopping, cooking, writing, and watching TV may be hard to do.(NEI) Low vision is less than 20/40 with glasses, decreased contrast sensitivity, scotomas (blind spots in the vision), and decreased visual fields (peripheral vision loss).
What is Low Vision?
There are several common patterns of vision and vision loss, including…
Central vision is the portion of our vision used for reading and fine vision tasks. When you look directly at a persons face you are using your central vision to see their face. The part of the eye used in central vision is call the macula. Macular degeneration seen in conditions like Age Related Macular Degeneration and Macular edema or swelling from Diabetes are common causes of central vision loss.
Peripheral vision is everything outside of central vision. You use peripheral vision when driving to see cars or pedestrians to your sides. When you see something moving at your side you are using your peripheral vision. You might then turn to look at it and use your finer central vision to see it in more detail. Glaucoma, retinal detachments, and strokes might cause peripheral vision loss.
Generalized vision loss
Generalized vision loss can involve both the central and peripheral vision. People with this type of vision loss have difficulty in situations that require fine detail, reading and driving. Generalized vision loss can have many different causes.
Low Vision Causes
Most people with low vision are age 65 or older. The leading causes of vision loss among older adults include age-related macular degeneration, cataract, diabetic retinopathy, glaucoma and strokes. With the aging of the population, the prevalence of these diseases and conditions is on the rise.(NEI) When vision loss is no longer treatable, vision rehabilitation is critical. Learn more about the conditions leading to vision loss below…
Macular Degeneration is often age related but can be caused by medications and other conditions.
Macular degeneration often leaves a dark, blurry, or wavy spot in the center of vision. This can be very frustrating as it obscures what you are trying to focus on. The macula is the part of the sensory retina we use for fine vision like reading or watching TV.
There are two main types of Age Related Macular Degeneration, wet and dry. There is currently no treatment for dry macular degeneration. Your ophthalmologist will likely recommend you check an amsler grid daily and take special vitamins for eye health. For wet macular degeneration, ophthalmologists treat with injections of a special medication or laser. It is important to see an ophthalmologist for any changes in your amsler grid. There are many vision rehabilitation techniques to assist people with central vision loss. For example, therapists may teach eccentric fixation–a technique where you learn the location of your best vision and practice placing your object of interest in this location.
Cataracts can be part of the natural aging process or due to medications, illnesses or trauma. Cataracts can increase glare when driving at night or make you feel like your vision isn’t good even with your glasses.
Optometrists and ophthalmologists can complete a dilated eye exam to look for cataracts. This exam is painless and dilation resolves in a few hours. Ophthalmologists can also remove your cataract in a painless outpatient surgery. This surgery improves vision loss.
Diabetes types 1 or 2 can damage the blood vessels and nerves in the body and eyes.
This can lead to vision loss and blurry vision. If you have diabetes, you should have your eyes checked yearly by your optometrist or ophthalmologist. They will conduct a dilated eye exam to look for signs of retinopathy. It is important to manage your blood sugars to reduce the risk of damage to the eye and your vision. If you notice changes in your vision see your ophthalmologist.Diabetic retinopathy is best prevented, but if you have diabetic retinopathy your ophthalmologist may treat you with special medication injections, laser, or surgery. If you develop permanent vision loss from diabetes, vision rehabilitation can help improve your function and quality of life.
Glaucoma is a condition that leads to areas of vision loss in the central or peripheral vision.Glaucoma can be open angle or closed angle. Depending on the type of glaucoma and severity you may be treated with eye drops, laser, or surgery. When you visit your optometrist or ophthalmologist they may screen for glaucoma by checking your eye pressure, examining your optic nerve, checking a visual field test or taking pictures of your nerves. Glaucoma is usually a slowly progressive disease. You may not even be aware of peripheral vision loss until it is severe. Severe peripheral vision loss can make you feel like you have tunnel vision. This may impact driving safety. Vision rehabilitation can help you take charge of your remaining sight.
Stroke (Brain or Eye)
It is common with hypertension, heart beat irregularities, diabetes, and
blood clotting issues to have a problem with blood flow to the brain or the eye. A stroke can cause vision loss that results in a blind spot that is the same in both eyes. It is also possible to lose blood flow to the eye which can result in total or partial vision loss, usually only in the affected eye. Brain and Vision rehabilitation are useful in the setting of stroke.
Other Causes of Vision Loss
There are many infections, injuries and diseases that can cause vision loss. Regardless of the reason you have vision loss, vision rehabilitation specialists can use your remaining vision and your goals to maximize your independence and enjoyment of life.
Vision rehabilitation takes many forms and is individualized for each patient based on the goals and remaining vision. Vision rehabilitation is a partnership with a trained therapist. Our Occupational Therapists offer information, strategies and resources that patient’s need to lead successful, productive and independent lives. They provide specialized methods or adaptive techniques for communication and coping with the demands of daily living.
The first steps to maximizing vision include…
Make it bigger.
There are many types of magnifiers that can make it easier to see. Simple hand held magnifiers, lighted stand magnifiers, and computerized magnifiers can all help in different situations. Your therapist will help you find the right tools and learn how to use them.
Make it brighter.
Higher contrast makes seeing easier. Many readers, phones and computers have contrast settings that can be changed. Good task lighting will also increase readability.
Mobility is important to maintaining independence and quality of life. It is important to have a safe environment and learn mobility techniques that leverage your remaining vision.