Dry Macular Degeneration

Three Stages of Macular Degeneration

Educating yourself about health conditions. Peter Cade

Dry age-related macular degeneration (AMD) is the most common type of the disease, accounting for about 90% of all AMD cases. In dry AMD, an observable change in the pigmented cells of the eye occurs, leaving areas of depigmentation, pigment clumping, and drusen. Dry macular degeneration is also called non-exudative macular degeneration.

Dry AMD usually progresses very slowly. The amount of vision loss with dry AMD varies, but it rarely progresses to legal blindness.

Some patients may develop macular tissue atrophy and mild scarring. Dry AMD occurs in three stages referred to as early, intermediate, and advanced AMD.

Early Stage Dry AMD

The most common observation in the early stage of dry AMD is the presence of drusen. Drusen is made up of small yellow material that builds up within the retina. Drusen is easily detectable by your eye doctor during a dilated eye examination. Most people with early AMD do not have reduced vision. In fact, vision in many cases is still 20/20.

Intermediate Stage Dry AMD

Intermediate AMD occurs with the presence of one or more large drusen or an irregularly shaped drusen. People in the intermediate stage typically have more symptoms than those in the early stage, often complaining of blurred vision and needing more light to read. Objects may sometimes appear distorted in the central vision and a scotoma (blind spot) may also develop.

Advanced Stage Dry AMD

Advanced AMD is also called geographic AMD. In this stage, pigmentary changes begin to appear in the retina, and the light-sensitive layer of the retina breaks down. Scarring may create significant distortion in the central vision. Central blind spots become much larger, making it extremely difficult or impossible to read or use straight-ahead central vision.

 People with advanced stage dry AMD begin to make more use of their peripheral vision, which remains intact. People with advanced AMD do not go blind as they retain their peripheral vision and make very good use of it. However, it can cause significant loss of central vision.

Sources:

Alexander, Larry J. Primary Care of the Posterior Segment, Second Edition. Appleton & Lange, 1994.

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