Health Guide » 
Topic Overview
Age-related macular degeneration (AMD) is an eye disease that destroys central vision by damaging the macula. The macula is part of the retina, a thin layer of nerve cells that lines most of the inside of your eyeball. Nerve cells in the retina detect light and send signals to the brain about what your eye sees. The macula is near the center of the retina at the back of the eyeball and provides the clear, sharp, central vision that you use for focusing on what is in front of you. The rest of the retina provides side (peripheral) vision.
Because AMD does not affect side vision, it does not lead to total blindness. It does cause central vision loss, however, which can be devastating. Central vision is the most important part of your vision. It lets you see shapes, colors, and details sharply and clearly and lets you see what is directly ahead of you.
There are 2 types of age-related macular degeneration. Either type may affect one or both eyes.
- Dry age-related macular degeneration is the most common form (90% of cases) and does not usually cause severe vision loss. Central vision slowly becomes dimmer or more blurry as the person gets older.
- Wet age-related macular degeneration is much less common (10% of cases). It can damage the macula quickly and cause rapid and severe loss of central vision.
What are the benefits of being fit?
Fitness reduces your risk of dying early and of developing diseases such as high blood pressure , coronary artery disease , and diabetes . Fitness also leads to an improved sense of well-being, improved appearance, enhanced social life, and increased stamina and strength.
What types of activities improve fitness?
Most experts agree that there are three components of fitness:
- Flexibility is the ability to move joints and use muscles through their full range of motion. Stretching is a flexibility exercise.
- Aerobic fitness conditions your heart and lungs. It increases the amount of oxygen that is delivered to your muscles, which allows them to work longer. Walking is a type of aerobic exercise.
- Muscle strengthening includes building more powerful muscles and increasing how long you can use them (endurance). Weight lifting builds stronger muscles and strengthens bones, while push-ups build endurance.
Keep in mind that you may be fairly fit in one area (perhaps aerobic fitness) but just getting started with another (such as flexibility or muscle strengthening).
How do I get started?
To become fit, you must be physically active. This can involve participating in sports, structured exercise with others, or exercising on your own. However, physical activity can also come through everyday activities, such as washing your car yourself instead of going to a car wash, or participating in hobbies that increase activity, such as joining a gardening club or dancing. However, these activities have to be done on a regular basis to gain fitness.
