amaurosis

Vision impairment is the loss of vision. It includes blindness, which means that you have lost all or most of your sight. It also includes low vision, which means you have some vision, but the vision loss makes it hard to do everyday activities. You may have trouble reading, shopping, cooking, writing, and watching TV. Low vision can't be fixed with glasses, contact lenses, medicine, or surgery.

Aging doesn't cause vision loss on its own. But many diseases that are more common in older adults can cause it. The leading causes of low vision and blindness in the United States are age-related eye diseases such as macular degeneration, cataracts, and glaucoma. Other eye disorders, eye injuries, and birth defects can also cause vision loss.

Vision impairment is diagnosed with a dilated eye exam. Early warning signs of a vision problem can include not being able to see well enough to:

• Do everyday tasks like reading and driving
• Recognize people's faces
• Tell the difference between colors
• See the television or computer screen clearly

You can have these symptoms even though you are wearing glasses or contacts.

There are several types of low vision. Which type you have depends on the condition that caused your low vision.

Common types of low vision include:

• Central vision loss (not being able to see things in the center of your vision)
• Peripheral (side) vision loss (not being able to see things out of the corners of your eyes)
• Night blindness (not being able to see in low light)
• Blurry or hazy vision

Low vision is permanent. Glasses, medicine, and surgery can't cure low vision. But sometimes they can improve your vision, help you do everyday activities more easily, or keep your remaining vision.

Your treatment options will depend on the condition that caused your low vision. Ask your eye doctor which treatments might help you. They may recommend vision aids or vision rehabilitation, which might make everyday activities easier.

Vision rehabilitation teaches you how to live with your vision loss. It may include:

• Showing you how to use a magnifying device or screen readers for reading
• Helping you set up your home so you can move around more easily
• Employment and job training
• Assistive devices, like lighting and reading stands

Your provider may suggest other resources, such as transportation and household services, to help you cope with your vision loss.

The sooner vision loss or eye disease is found and treated, the greater your chances of keeping your remaining vision. Whatever the cause, lost vision cannot be restored. But it can be managed. A loss of vision means you may have to reorganize your life and learn new ways of doing things. Your provider may make suggestions to help make life easier. These may include:

If you have some vision:

• Visual aids such as magnifiers
• Telescopic glasses or monoculars for seeing distance
• Large print books
• Clocks with larger numbers
• Brighter lights
• Anti-glare sunglasses or glare shields

If you have no vision (blindness):

• Devices like text-reading software and braille books

You can help take care of your vision by:

• Having regular comprehensive eye exams by an eye care professional
• Wearing sunglasses and protective eyewear to protect your eyes
• Making lifestyle changes to lower your risk of health conditions that can cause vision problems:
  • Getting regular physical activity
  • Staying at a healthy weight
  • Quitting smoking (or not starting)
  • Eating a healthy diet

NIH: National Eye Institute

Most of us see our world in color. We enjoy looking at a lush green lawn or a red rose in full bloom. If you have a color vision defect, you may see these colors differently than most people.

There are three main kinds of color vision defects. Red-green color vision defects are the most common. This type occurs in men more than in women. The other major types are blue-yellow color vision defects and a complete absence of color vision.

Most of the time, color blindness is genetic. There is no treatment, but most people adjust and the condition doesn't limit their activities.

Diabetes is a disease in which your blood glucose, or blood sugar, levels are too high. Glucose comes from foods you eat. The cells of your body need glucose for energy. A hormone called insulin helps the glucose get into your cells.

With type 1 diabetes, your body doesn't make insulin. With type 2 diabetes, your body doesn't make or use insulin well. Without enough insulin, glucose builds up in your blood and causes high blood glucose levels.

Over time, high blood glucose may damage the blood vessels and lenses in your eyes. This can lead to serious diabetic eye problems which can harm your vision and sometimes cause blindness. Some common diabetic eye problems include:

• Diabetic retinopathy, which is the leading cause of blindness in American adults. It affects blood vessels in the retina (the light-sensitive layer of tissue in the back of your eye). The blood vessels may swell and leak fluid into your eye. If it's not treated, it can cause serious problems such as vision loss and retinal detachment, where the retina is pulled away from its normal position at the back of your eye.
• Diabetic macular edema (DME), which happens when blood vessels in the retina leak fluid into the macula (the part of the retina needed for sharp, central vision). This usually develops in people who already have other signs of diabetic retinopathy.
• Glaucoma, a group of eye diseases that can damage the optic nerve (the bundle of nerves that connects the eye to the brain). Glaucoma from diabetes happens when the blood vessels in the front of your eye are damaged, and new blood vessels grow near the iris (the colored part of your eye). The blood vessels block the space where fluid drains from your eye. This causes fluid to build up and pressure to increase inside your eye.
• Cataract, which is the leading cause of blindness worldwide. It happens when the clear lens in the front of your eye becomes cloudy. Cataracts are common as people age. But people with diabetes are more likely to develop cataracts younger and faster than people without diabetes. Researchers think that high glucose levels cause deposits to build up in the lenses of your eyes.

Anyone with diabetes can develop diabetic eye disease. But your risk of developing it is higher if you have diabetes and:

• Have had diabetes for a long time
• Don't have good control over your high blood glucose or high blood pressure
• Are pregnant
• Have high blood cholesterol
• Smoke tobacco

In the early stages, diabetic eye problems usually don't have any symptoms. That's why regular dilated eye exams are so important, even if you think your eyes are healthy.

You should also watch for sudden changes in your vision that could be signs of an emergency. Call your eye care professional right away if you notice any of these symptoms:

• Many new spots or dark wavy strings floating in your vision (floaters)
• Flashes of light
• A dark shadow over part of your vision, like a curtain
• Vision loss
• Eye pain or redness

Talk with your eye care professional if you have these symptoms, even if they come and go:

• Spots or dark wavy strings floating in your vision
• Blurry or wavy vision
• Vision that changes a lot
• Trouble seeing colors

Eye care professionals do dilated eye exams to diagnose eye problems. A dilated eye exam uses eye drops to open your pupils wide so your eye care professional can look for signs of eye problems and treat them before they harm your vision. They will also test your vision and measure the pressure in your eyes.

Treatment for diabetic eye problems depends on the problem and how serious it is. Some of the treatments include:

• Lasers to stop blood vessels from leaking
• Injections (shots) in the eye to stop new, leaky blood vessels from growing
• Surgery to remove blood and scar tissue or replace a cloudy lens
• Eye drops to lower fluid pressure in the eye

But these treatments aren't cures. Eye problems can come back. That's why your best defense against serious vision loss is to take control of your diabetes and get regular eye exams. It's also important to keep your blood pressure and cholesterol in a healthy range.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

Retinal disorders are conditions that affect the retina, the thin light-sensitive tissue at the back of your eye. The retina senses light and sends signals to your brain so you can see.

Retinal disorders can cause blurred or distorted vision. Some can lead to vision loss or blindness.

The causes of retinal disorders vary. Aging is a common factor, but other things can raise your risk, such as if you:

• Smoke
• Have obesity
• Have health conditions like diabetes or high blood pressure
• Have had an eye injury or trauma
• Have a family history of retinal disorders

Some common retinal disorders include:

• Macular degeneration. Occurs when the macula (the center of the retina that helps you see fine details) breaks down. There are two types: wet and dry macular degeneration.
• Diabetic retinopathy. Occurs when diabetes damages small blood vessels in the retina, causing them to swell or leak.
• Retinal detachment. Occurs when the retina pulls away from the back of the eye. This is a medical emergency.
• Retinal tears. A hole or break in the retina caused when the gel-like substance inside your eye (the vitreous) pulls away.
• Retinoblastoma. A rare cancer of the retina that most often affects young children.
• Macular pucker. Scar tissue that forms on the macula and distorts vision.
• Macular hole. A small opening in the macula, often related to aging or injury. It can blur or distort central vision.
• Eye floaters. Small specks, cobwebs, or threads that drift across your vision. These are more common with aging.
• Retina pigmentosa. A group of inherited disorders (passed down through families) that slowly damage the retina and cause loss of night and side (peripheral) vision.

Symptoms can vary, but most retinal disorders affect your vision. Common symptoms include:

• Blurred or distorted vision
• Loss of central or side (peripheral) vision
• Flashes of light
• Seeing floating specks or cobwebs
• Trouble seeing at night
• Sudden vision loss (in severe cases)

Seek medical care right away if you notice flashes of light, sudden vision changes, or a sudden increase in eye floaters. These can be signs of a serious retinal problem.

Eye care providers check for retinal disorders with a dilated eye exam. Eye drops are used to widen your pupils so your provider can look at the retina for signs of damage.

They may also do other tests, such as:

• Optical coherence tomography (OCT) to take detailed pictures of the inside of your eye.
• Fluorescein angiography to check the blood vessels in your retina.
• Visual field tests to measure your side (peripheral) vision.

Some retinal disorders can be treated to slow or stop vision loss, and sometimes to restore vision. Treatment depends on the cause and severity. It may include:

• Laser therapy
• Medicine or eye injections
• Surgery
• Lifestyle management to control health conditions such as diabetes or high blood pressure

Not all retinal disorders can be prevented. Some are related to aging or genetics. But you can protect your eyes by:

• Wearing safety goggles or sunglasses
• Getting regular eye exams
• Making healthy lifestyle changes, such as:
  • Quitting smoking (or not starting)
  • Managing diabetes and blood pressure

NIH: National Eye Institute

Glaucoma is a group of diseases that can damage the optic nerve of one, or both, of your eyes. This can result in vision loss. There are different types of glaucoma, but the most common type is open-angle glaucoma. Other less common types include angle-closure glaucoma, and congenital glaucoma.

You may not have any symptoms of glaucoma. Regular eye exams by an eye care provider can check for glaucoma and other eye problems to help protect your vision. Treatments that lower eye pressure help slow the disease. Without treatment, glaucoma can eventually lead to blindness.

Medical experts aren't sure what causes glaucoma, but the most common types usually happen when the fluid pressure inside your eye slowly rises, damaging the optic nerve. Other types of glaucoma may be caused by medical conditions, or a baby may be born with it.

Not everyone with high eye pressure develops glaucoma. Some people may even get glaucoma with normal eye pressure. The amount of pressure your optic nerve can handle is different for each person. Getting regular dilated eye exams helps your provider figure out what level of eye pressure is normal for you.

Often there are no symptoms of glaucoma at first. Or symptoms may start so slowly that you may not notice them. Without treatment, you slowly lose your peripheral (side) vision. It may seem like you're looking through a tunnel. Over time, your straight-ahead vision may decrease until no vision remains.

If you have sudden symptoms of intense eye pain, blurry vision, red eyes, or an upset stomach (nausea), you need to go to your eye care provider or an emergency room right away. These could be symptoms of angle-closure glaucoma. This less common type of glaucoma causes fluid to build up quickly in your eye.

A comprehensive eye exam can tell if you have glaucoma. This would include:

• A dilated eye exam. This involves getting eye drops that dilate (widen) your pupils. This allows more light to enter your eye. Your eye care provider examines your eyes using a special magnifying lens. This provides a clear view of important tissues at the back of your eye to check for glaucoma or other eye problems. For a few hours after the exam your vision may be blurry and sensitive to light, so you will need someone to take you home.
• Visual field testing. This check of your peripheral (side) vision allows your eye care provider to find out how well you can see objects off to the side of your vision without moving your eyes.
• Tonometry. This measures the pressure inside your eye.

If you're at higher risk for glaucoma, you should get comprehensive eye exams every one to two years. You're at higher risk if you:

• Are Black or African American and over age 40
• Are over age 60, especially if you're Hispanic or Latino
• Have a family history of glaucoma

You're also at higher risk if you have high blood pressure or diabetes and should get a dilated eye exam at least once a year. Talk with your provider about your risk and how often you should get your eyes checked.

Early treatment can help protect your eyes against vision loss. There is no cure, but glaucoma can usually be controlled. Without treatment it can eventually cause blindness. Treatments can include:

• Prescription eye drops are the most common treatment to lower the pressure in your eye and prevent damage to your optic nerve.
• Other treatments may include oral medicines, laser treatment, and/or surgery.

A combination of these treatments may be used to lower eye pressure and help drain the fluid out of your eye.

There is no way to prevent glaucoma. Eye exams can help find glaucoma or other eye problems before they can affect your vision. If you have glaucoma, be sure to continue with treatment to prevent your vision from getting worse.

NIH: National Eye Institute

Behcet's syndrome is a disease that involves vasculitis, which is inflammation of the blood vessels. It causes problems in many parts of the body. The most common symptoms are:

• Sores in the mouth
• Sores on the sex organs
• Other skin sores
• Swelling of parts of the eye
• Pain, swelling and stiffness of the joints

More serious problems can include meningitis, blood clots, inflammation of the digestive system and blindness.

Doctors aren't sure what causes Behcet's. It is rare in the United States, but is common in the Middle East and Asia. It mainly affects people in their 20s and 30s. Diagnosing Behcet's can take a long time, because symptoms may come and go, and it may take months or even years to have all of the symptoms. There is no cure. Treatment focuses on reducing pain and preventing serious problems. Most people can control symptoms with treatment.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Developmental disabilities are conditions that are usually present at birth. They can affect a child's growth and development. These conditions can cause physical, learning, language, or behavior issues. They can include:

• Learning disabilities. These conditions affect the ability to learn.
• Autism spectrum disorder (ASD). This is a disorder that affects behavior, communication, and social skills.
• Cerebral palsy (CP). This is a condition that affects movement, coordination, and balance.
• Physical disabilities. These could include blindness or deafness.
• Conditions that can affect both physical and mental abilities. This could include Down syndrome.

These conditions can cause lifelong challenges in learning. Completing daily tasks may be difficult. Early treatment may help your child learn important skills and make the most of their strengths.

Developmental disabilities are often present at birth. They can occur due to various reasons. These can include:

• Genetic or chromosome abnormalities. These cause conditions such as Down syndrome, Fragile-X-Syndrome, and Rett syndrome.
• Use of substances while pregnant. For example, drinking alcohol when pregnant can cause fetal alcohol spectrum disorders.
• Certain infections during pregnancy.
• Preterm birth or low birth weight.

The way a developmental disability is diagnosed depends on the condition. Screening tests or a physical exam may be done to check for a medical problem. Other tests and questionnaires may help find out if your child has a developmental disability. These may include:

• Screening tests that are done during pregnancy or for newborns
• Developmental and behavioral screening tests or questionnaires to check if your child is developing on schedule
• Observing your child's behavior and how they interact with other people
• Testing your child's intellectual and school performance
• Asking about your family history

If your child has a developmental disability, these are usually lifelong conditions. Often, there is no cure, but treatment can help the symptoms. Treatments can include:

• Physical, speech, and occupational therapy
• Special teaching methods
• Psychological counseling
• To keep track of how your child grows and changes over time

NIH: National Institute of Child Health and Human Development

Eye care is about keeping your eyes healthy through good daily habits, regular checkups, and treatment when needed. Your eyes are an important part of your health. You rely on them every day to see and understand the world around you. Some eye diseases can lead to vision loss without early warning signs, so it's important to catch them as soon as possible. Get your eyes checked as often as your health care provider recommends, or if you notice new vision problems. Just like caring for the rest of your body, it's important to keep your eyes healthy.

There are many things you can do to protect your eyes and see your best:

• Give your eyes a rest. Spending long hours on a computer or other digital screens can make you blink less, causing dryness and tired eyes. To reduce eyestrain, try the 20-20-20 rule: Every 20 minutes, look away about 20 feet in front of you for 20 seconds.
• Wear sunglasses.Sun exposure can damage your eyes and raise your risk of cataracts and age-related macular degeneration. Protect your eyes by using sunglasses that block out 99 to 100% of both UV-A and UV-B radiation.
• Wear protective eyewear. To prevent eye injuries, you need eye protection when playing certain sports, working in jobs such as factory work and construction, and doing repairs or projects in your home.
• Avoid rubbing your eyes. Rubbing your eyes can transfer dirt and bacteria that may cause irritation or lead to an infection.
• Use good lighting. Brighten your space to reduce strain and help you see comfortably.
• If you wear contacts, take steps to prevent eye infections. Wash your hands before you put in or take out your contact lenses. Also follow the instructions on how to properly clean them and replace them when needed.

What you eat and how you take care of your body can have a big impact on your eyes and vision:

• Eat a healthy, balanced diet. Your diet should include plenty of fruits and vegetables, especially dark leafy green vegetables like spinach, kale, or collard greens. Eating fish high in omega-3 fatty acids, such as salmon, tuna, and halibut can also help your eyes.
• Maintain a healthy weight. Being overweight or having obesity increases your risk of developing diabetes. Having diabetes puts you at higher risk of getting diabetic retinopathy or glaucoma.
• Get regular exercise. Exercise may help to prevent or control diabetes, high blood pressure, and high cholesterol. These diseases can lead to some eye or vision problems. Regular exercise helps lower your risk.
• Avoid smoking. Smoking increases the risk of developing age-related eye diseases such as macular degeneration and cataracts and can damage the optic nerve.
• Know your family medical history. Some eye diseases are inherited (passed down through families), so it is important to find out whether anyone in your family has had them. This can help you determine if you are at higher risk of developing an eye disease.
• Know your other risk factors. As you get older, you are at higher risk of developing age-related eye diseases and conditions. It is important to know your risk factors because you may be able to lower your risk by changing some behaviors.

Everyone needs their eyesight tested to check for vision and eye problems. Children usually have vision screening, also called an eye test, in school or at their provider's office during a checkup. This is a brief test that mainly checks how well you can see things up close and far away. Adults may also get vision screenings during their checkups. But many adults need more than a vision screening. They need a comprehensive dilated eye exam.

Getting comprehensive dilated eye exams is especially important because some eye diseases may not have warning signs. The exams are the only way to detect these diseases in their early stages, when they are easier to treat.

The eye exam includes several tests:

• Test your side (peripheral) vision with a visual field test. Losing peripheral vision may be a sign of glaucoma.
• Check how well you see at various distances with a visual acuity test, where you read an eye chart about 20 feet away.
• Follow an object with your eyes during an eye muscle function test to check for problems with the muscles that control your eyes.
• Shine a light into your eyes with a pupil response test to see how your pupils react to light.
• Measure the pressure inside your eyes with tonometry. This test helps to detect glaucoma.
• Dilate (widen) your pupils with special eye drops allows more light to enter the eye. Your eye care provider then uses a special magnifying lens to clearly see important tissues at the back of your eye, including the retina, macula, and optic nerve.

If you have a refractive error and are going to need glasses or contacts, then you will also have a refraction test. When you have this test, you look through a device that has lenses of different strengths to help your eye care professional figure out which lenses will give you the clearest vision.

How often you need eye exams depends on your age, race, risk factors, and overall health. For example, Black/African American adults are at higher risk for glaucoma and may need to start exams earlier. If you have diabetes, you should have an exam every year. Check with your provider about when you need these exams.

See an eye care specialist right away if you have symptoms like sudden loss of vision, double vision, blurred vision with eye pain, flashes of light, black spots or halos around lights. These symptoms may represent a serious medical or eye condition.

Even if your eyes feel healthy, you could have a problem and not know it. That's why regular eye exams are so important. Refractive errors are the most common type of vision problem that makes it hard to see clearly. But some eye conditions or diseases don't have any symptoms and can lead to a permanent loss of vision.

Some common eye diseases and conditions include:

• Cataracts, which happens when the clear lens in the front of your eye becomes cloudy. Cataracts are common as you get older and can lead to vision loss.
• Optic nerve disorders, which includes glaucoma. Glaucoma usually happens when the fluid pressure inside your eyes slowly rises.
• Retinal disorders, which are problems with the nerve layer at the back of your eye.
• Macular degeneration, which is a disease that destroys your sharp, central vision.
• Diabetic eye problems, which can cause vision loss and blindness.
• Conjunctivitis, which is an infection also known as pink eye. It can cause pink or red itchy eyes. Some types of pink eye can spread very easily.

Some eye conditions and diseases do not always have symptoms. Early detection through a comprehensive dilated eye exam could help your eye care provider detect diseases in the early stages. Proper treatment could help slow or prevent vision loss.

Get regular eye exams and call your eye care professional right away if you notice any of these symptoms:

• A sudden change in vision
• Everything looks dim
• Flashes of light
• Eye pain
• Double vision
• Fluid coming from your eye
• Inflammation (swelling)

Getting older increases your risk of some eye diseases. Other things that may put you at a higher risk of some eye diseases can include if you:

• Are overweight or obese
• Have a family history of eye disease
• Are African American, Hispanic, or Native American
• Have certain health conditions such as Diabetic eye problems, or high blood pressure

Treatment may depend on the eye condition or disease but can include:

• A new prescription for eyeglasses or contacts
• Use of bright lights or magnifying lenses for reading and other activities
• Medicines
• Prescription eye drops or ointments
• Laser treatment
• Surgery

Depending on your eye condition or disease, treatment may slow vision loss but may not restore vision. Talk to your provider about what treatment is best for you.

Your best defense is to have regular checkups. Be sure to tell your provider if any eye diseases run in your family.

You can also help take care of your vision by making lifestyle changes to lower your risk of health conditions that can cause vision problems. This could include by:

• Protecting your eyes from the sun
• Wearing protective eyewear while using tools or playing certain sports
• Getting regular physical activity
• Staying at a healthy weight
• Quitting smoking (or not starting)
• Eating a healthy diet

NIH: National Eye Institute

Genes are sections of DNA in your cells that are passed down (inherited) from your parents. You inherit two copies of each gene, one from each parent. Genes carry information that controls what you look like and how your body works.

There are about 20,000 genes that provide instructions for making proteins, which your body needs to work correctly.

Some genes don't make proteins themselves but instead help control how other genes work. They act like switches, turning other genes on or off. This means they help decide when, where, and how much of a protein is made in your body.

Changes in your genes are also called gene variants or mutations. These changes can be inherited, occur as you age, or result from environmental factors such as chemicals or radiation. Often, these changes have no effect, but sometimes, even a small change in the DNA can alter the instructions for making proteins. If genes don't make the right proteins, or don't make them correctly, this can cause a genetic disorder.

Gene therapy uses genes to treat or prevent disease by correcting genetic problems. It works by changing your genetic material, rather than relying on traditional treatments like medicine or surgery.

New genetic material can be delivered into cells in two main ways:

• ex-vivo treatment. Cells are removed from your body, modified by adding genetic material, and then placed back into your body.
• in-vivo treatment. Genetic material is delivered directly into your body, often through an injection.

A common form of gene therapy involves inserting a normal gene to replace an abnormal gene. Other approaches include:

• Repairing an abnormal gene
• Altering the degree to which a gene is turned on or off

Newer techniques offer different ways to correct genetic problems:

• Genome editing (also called gene editing). Instead of adding new genetic material into cells, this approach changes the DNA that's already in your cells. A well-known example is CRISPR-Cas9. This promising technique is still being studied and may soon be used to treat genetic disorders.
• Cell-based gene therapy combines gene therapy and cell therapy. An example of this would be CAR T cell therapy. Cells, which are often immune system cells, are genetically altered to help treat a disease and then introduced into the body.

Gene therapies are currently only approved to treat a small number of diseases, such as:

• Leber congenital amaurosis, an inherited eye disorder.
• Spinal muscular atrophy, a genetic muscle disorder.

While gene therapy holds great promise, it comes with risks and challenges. Studies are still ongoing to ensure these treatments are safe and effective. Some challenges include:

• Immune system reactions. Your body may see the new material as a threat and react to it.
• Unintended effects. Changes to DNA could affect other genes in harmful ways.
• High costs. Gene therapies are often expensive and are not widely accessible.