Retinal Diseases: Age-Related Macular Degeneration and Retinitis Pigmentosa

Age-related macular degeneration (AMD) is an eye disease primarily affecting the central vision regions in people age 60 and older. According to the Macular Degeneration Research Fund, a case of AMD is diagnosed in the United States every 3 minutes. Each year, 1.2 million of the estimated 12 million people with AMD will suffer severe vision loss. Patients with AMD have dark areas in their vision caused by fluid leakage or bleeding in the macula, the center of the retina that produces the sharpest vision. The brain initially compensates for these dark patches. Early cellular dysfunction or spotting in the macula may go undetected until the disease is in advanced stages.

Retinitis pigmentosa (RP) is the most common inherited cause of blindness in people between the ages of 20 and 60 worldwide. Around 500,000 people in the United States suffer some level of visual impairment from RP, and, of those, 20,000 are totally blind. RP is a degenerative disease of the retina that affects the photoreceptor, or rod cells, which control a person’s ability to see in dimly lit surroundings. Vision loss is gradual and may result in diminished or lost peripheral vision or blindness.

A person with normal vision has frontal and peripheral vision, as shown in the example above. The eye can see an image by interpreting light hitting the back light-sensing cells, the rods and cones which line the retina. If something happens to these cells, then vision distortion or even blindness occurs. (Eye illustration courtesy of National Eye Institute, National Institutes of Health.)

How RP and AMD Affect Vision

A person with retinitis pigmentosa (RP) loses much of their peripheral vision and sees an effect sometimes called “tunnel vision.” A person with age-related macular degeneration (AMD) loses some vision usually in the center of their field-of-vision.