retinitis

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

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

Cytomegalovirus (CMV) is a virus found around the world. It is related to the viruses that cause chickenpox and infectious mononucleosis (mono). Between 50% and 80% of adults in the United States have had a CMV infection by age 40. Once CMV is in a person's body, it stays there for life.

CMV is spread through close contact with body fluids. Most people with CMV don't get sick and don't know that they've been infected. But infection with the virus can be serious in babies and people with weak immune systems. If a woman gets CMV when she is pregnant, she can pass it on to her baby. Usually the babies do not have health problems. But some babies can develop lifelong disabilities.

A blood test can tell whether a person has ever been infected with CMV. Most people with CMV don't need treatment. If you have a weakened immune system, your doctor may prescribe antiviral medicine. Good hygiene, including proper hand washing, may help prevent infections.

Centers for Disease Control and Prevention

Your eyes can get infections from bacteria, fungi, or viruses. Eye infections can occur in different parts of the eye and can affect just one eye or both. Two common eye infections are:

• Conjunctivitis - also known as pink eye. Conjunctivitis is often due to an infection. Children frequently get it, and it is very contagious.
• Stye - a bump on the eyelid that happens when bacteria from your skin get into the hair follicle of an eyelash.

Symptoms of eye infections may include redness, itching, swelling, discharge, pain, or problems with vision. Treatment depends on the cause of the infection and may include compresses, eye drops, creams, or antibiotics.

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.