Macular Degeneration--What is it? Part 1 of 3

Age Related Macular Degeneration (ARMD or AMD) recently hit the spotlight when a famous actress, Dame Judi Dench, was diagnosied with it.  AMD is a disease associated with the painless loss of your sharp central vision that you use to see the fine details of life. 

The macula is a geographic area in the retina which is reponsible for giving you the sharpest vision.  ALL of the light that enters your eye focuses on the macula.  So if the tissue is damaged, your vision will not be sharp.

There are 2 forms of macular degeneration:  wet and dry.

Dry macular degeneration occurs when deposits, called drusen, develop under the surface of the macula.  Drusen may progress to a point where a breakdown occurs in the ability of the tissue to process vision and eventually lead to vision loss.

Wet macular degeneration happens when abnormal blood vessels grow under the surface of the macula.  These vessels are weak and bleed easily and quickly cause significant loss of vision. 

I like to use analogies so my patients can better "visualize" disease processes.  For macular degeneration, I like patients to think of their retinas like their lawn.  The blades of grass are like the rods and cones of their retina, and we want them to be straight up and down for the sharpest vision.  In dry macular degeneration, we get early weed growth that can distort the roots of the grass, which would translate to mild damage to the rods and cones.  In wet macular degeneration, think of a big weed that grows to the surface of the lawn and completely blocks the ability of the grass to grow, leading to significant rod and cone damage and therefore loss of vision.