pigmentosa

The retina is a layer of tissue in the back of your eye that senses light and sends images to your brain. In the center of this nerve tissue is the macula. It provides the sharp, central vision needed for reading, driving and seeing fine detail.

Retinal disorders affect this vital tissue. They can affect your vision, and some can be serious enough to cause blindness. Examples are:

• Macular degeneration - a disease that destroys your sharp, central vision
• Diabetic eye disease
• Retinal detachment - a medical emergency, when the retina is pulled away from the back of the eye
• Retinoblastoma - cancer of the retina. It is most common in young children.
• Macular pucker - scar tissue on the macula
• Macular hole - a small break in the macula that usually happens to people over 60
• Floaters - cobwebs or specks in your field of vision

NIH: National Eye Institute

Usher syndrome is an inherited disease that causes serious hearing loss and retinitis pigmentosa, an eye disorder that causes your vision to get worse over time. It is the most common condition that affects both hearing and vision.

There are three types of Usher syndrome:

• People with type I are deaf from birth and have severe balance problems from a young age. Vision problems usually start by age 10 and lead to blindness.
• People with type II have moderate to severe hearing loss and normal balance. Vision problems start in the early teens and get worse more slowly than in type I.
• People with type III are born with normal hearing and near-normal balance but develop vision problems and then hearing loss.

There is no cure. Tools such as hearing aids or cochlear implants can help some people. Training such as Braille instruction, low-vision services, or auditory training can also help.

NIH: National Institute on Deafness and Other Communication Disorders

Your skin is your body's largest organ. It covers the entire outside of your body. There are many ways that your skin protects your body and helps keep you healthy. For example, it:

• Holds body fluids in, which helps prevent you from getting dehydrated
• Keeps out harmful germs, which helps prevent infections
• Helps you feel things like heat, cold, and pain
• Helps control your body temperature
• Makes vitamin D when the sun shines on it
• Shields your body against heat and light

There are many different problems and conditions which can affect your skin. Some of them can cause uncomfortable symptoms, such as itching, burning, redness, and rashes. They might also affect your appearance. Some of the more common skin conditions include:

• Acne, which causes pimples when hair follicles under your skin get clogged up
• Burns
• Cuts and scrapes
• Dandruff, flaking of the skin on your scalp (the top of your head)
• Eczema (atopic dermatitis), which causes inflammation, redness, and irritation of the skin
• Hives, which are red and sometimes itchy bumps on your skin
• Insect bites
• Psoriasis, which causes itchy, scaly red patches
• Skin cancer
• Skin infections

Since your skin protects your body in many ways, it's important to try to keep your skin healthy. For example, you can:

• Wear the right protective equipment, like gloves, long sleeves, knee and elbow pads, or helmets to protect against cuts, bumps and scrapes.
• If you do get a cut or scrape, clean it right away with soap and warm water. Put on a bandage to protect it while it heals.
• When you are spending time outdoors, wear long sleeves and pants and use insect repellant to prevent insect bites.
• Prevent sunburn by covering up and using sunscreen when outdoors.
• Wash your hands often with soap and water.
• When you take a shower or bath, use warm (not hot) water. Use mild cleansers and wash gently (don't scrub).
• Use moisturizers, like lotions, creams, or ointments, to prevent dry skin.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

When you play the piano or hit a tennis ball you are activating the cerebellum. The cerebellum is the area of the brain that controls coordination and balance. Problems with the cerebellum include:

• Cancer
• Genetic disorders
• Ataxias - failure of muscle control in the arms and legs that result in movement disorders
• Degeneration - disorders caused by brain cells decreasing in size or wasting away

Treatment of cerebellar disorders depends on the cause. In some cases, there is no cure but treatment may help with symptoms.

NIH: National Institute of Neurological Disorders and Stroke

Itching is an irritating sensation that makes you want to scratch your skin. Sometimes it can feel like pain, but it is different. Often, you feel itchy in one area in your body, but sometimes you may feel itching all over. Along with the itching, you may also have a rash or hives.

Itching is a symptom of many health conditions. Some common causes are:

• Allergic reactions to food, insect bites, pollen, and medicines
• Skin conditions such as eczema, psoriasis, and dry skin
• Irritating chemicals, cosmetics, and other substances
• Parasites such as pinworms, scabies, head and body lice
• Pregnancy
• Liver, kidney, or thyroid diseases
• Certain cancers or cancer treatments
• Diseases that can affect the nervous system, such as diabetes and shingles

Most itching is not serious. To feel better, you could try:

• Applying cold compresses
• Using moisturizing lotions
• Taking lukewarm or oatmeal baths
• Using over-the-counter hydrocortisone cream or antihistamines
• Avoiding scratching, wearing irritating fabrics, and exposure to high heat and humidity

Contact your health care provider if your itching is severe, does not go away after a few weeks, or does not have an apparent cause. You may need other treatments, such as medicines or light therapy. If you have an underlying disease that is causing the itching, treating that disease may help.

Metabolism is the process your body uses to make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system (enzymes) break the food parts down into sugars and acids, your body's fuel. Your body can use this fuel right away, or it can store the energy in your body tissues. If you have a metabolic disorder, something goes wrong with this process.

Mitochondrial diseases are a group of metabolic disorders. Mitochondria are small structures that produce energy in almost all of your cells. They make it by combining oxygen with the fuel molecules (sugars and fats) that come from your food. When the mitochondria are defective, the cells do not have enough energy. The unused oxygen and fuel molecules build up in the cells and cause damage.

The symptoms of mitochondrial disease can vary. It depends on how many mitochondria are defective, and where they are in the body. Sometimes only one organ, tissue, or cell type is affected. But often the problem affects many of them. Muscle and nerve cells have especially high energy needs, so muscular and neurological problems are common. The diseases range from mild to severe. Some types can be fatal.

Genetic mutations cause these diseases. They usually happen before age 20, and some are more common in infants. There are no cures for these diseases, but treatments may help with symptoms and slow down the disease. They may include physical therapy, vitamins and supplements, special diets, and medicines.

Pigmentation means coloring. Skin pigmentation disorders affect the color of your skin. Your skin gets its color from a pigment called melanin. Special cells in the skin make melanin. When these cells become damaged or unhealthy, it affects melanin production. Some pigmentation disorders affect just patches of skin. Others affect your entire body.

If your body makes too much melanin, your skin gets darker. Pregnancy, Addison's disease, and sun exposure all can make your skin darker. If your body makes too little melanin, your skin gets lighter. Vitiligo is a condition that causes patches of light skin. Albinism is a genetic condition affecting a person's skin. A person with albinism may have no color, lighter than normal skin color, or patchy missing skin color. Infections, blisters and burns can also cause lighter skin.