Dry macular degeneration symptoms usually develop gradually and without pain. They may include:

• Visual distortions, such as straight lines seeming bent
• Reduced central vision in one or both eyes
• The need for brighter light when reading or doing close work
• Increased difficulty adapting to low light levels, such as when entering a dimly lit restaurant
• Increased blurriness of printed words
• Decreased intensity or brightness of colors
• Difficulty recognizing faces

Dry macular degeneration usually affects both eyes. If only one eye is affected, you may not notice any changes in your vision because your good eye may compensate for the weak eye. And the condition doesn't affect side (peripheral) vision, so it rarely causes total blindness.

Dry macular degeneration is one of two types of age-related macular degeneration. It can progress to wet (neovascular) macular degeneration, which is characterized by blood vessels that grow under the retina and leak. The dry type is more common, but it usually progresses slowly (over years). The wet type is more likely to cause a relatively sudden change in vision resulting in serious vision loss.

No one knows exactly what causes dry macular degeneration. But research indicates it may be related to a combination of heredity and environmental factors, including smoking and diet.

The condition develops as the eye ages. Dry macular degeneration affects the macula — an area of the retina that's responsible for clear vision in your direct line of sight. Over time tissue in your macula may thin and break down.

Factors that may increase your risk of macular degeneration include:

• Age. This disease is most common in people over 50.
• Family history and genetics. This disease has a hereditary component. Researchers have identified several genes that are related to developing the condition.
• Race. Macular degeneration is more common in Caucasians.
• Smoking. Smoking cigarettes or being regularly exposed to smoke significantly increases your risk of macular degeneration.
• Obesity. Research indicates that being obese may increase your chance that early or intermediate macular degeneration will progress to the more severe form of the disease.
• Cardiovascular disease. If you have had diseases that affected your heart and blood vessels, you may be at higher risk of macular degeneration.

People whose dry macular degeneration has progressed to central vision loss have a higher risk of depression and social isolation. With profound loss of vision, people may see visual hallucinations (Charles Bonnet syndrome). And dry macular degeneration may progress to wet macular degeneration, which can cause rapid vision loss if left untreated.