Macular Degeneration is a disease that affects the central part of the retina – the part that we call the macula.  The retina has two types of photoreceptor cells: rods and cones. 

Cones, which are mostly concentrated at the macula region of the retina, are responsible for more precise and sharp central vision and for color perception.

Rods, which are mostly found at the peripheral retina, are responsible for peripheral vision and contrast perception. 

Generally, we use our peripheral vision to detect movements and objects. When we need to distinguish what is moving, we direct our central vision (macula) to the object to see more precisely what this object is.

 

 

In macular degeneration, these rod and cone cells begin to lose their functions, degenerate and eventually die. The underlying tissues of these cells, which are Retinal Pigment Epithelium (RPE) and choroid, are also affected. RPE delivers oxygen and receives wastes from these retina cells and the blood supply is delivered by the large blood vessels of the choroid.  In case of a problem of this system, the cells cannot receive the oxygen and the wastes cannot be removed. Therefore, these tissues can no longer continue to do their jobs.  The photoreceptors (rods and cones) cannot send the visual signals through the optic nerve and, consequently, the patient cannot see.

In Age Related Macular Degeneration (ARMD), changes of these retinal tissues caused by age lead to the deterioration of this oxygen supply and waste removal system, which is the main reason of the disease.