The RETINA is the inner layer of the eyeball. It is composed of nerve tissue which
senses the light that enters the eye. These nerves send messages back to the brain which
translates the messages into the images that we see. The retina is a complex structure
with ten separate, but interconnected, layers. The center of the retina is the MACULA. The
macula is responsible for allowing detailed vision. The center of the macula is the FOVEA.
If the macula is healthy, normal (20/20) vision is possible. If the macula is damaged,
detailed vision is lost. The remainder of the retina is responsible for side, or
peripheral, vision.
The retinal nerve cells are RODS and CONES. The cones are
concentrated toward the center of the retina and are responsible for color vision. The
rods are more plentiful in the peripheral retina, and are responsible for "black-and-
white" vision in dim lighting.
The retina is prone to a variety of disease conditions. Systemic illnesses such as
diabetes and high blood pressure can cause permanent retinal damage. The retina also has
its own set of inherent disease conditions, all of which can threaten vision.