The cornea and lens focus light onto the retina, the transparent, light-sensitive membrane on the inner surface of the back of the eye. The central area of the retina, called the macula, contains a high density of color-sensitive photoreceptor (light-sensing) cells. These cells, called cones, produce the sharpest visual images and are responsible for central and color vision. The peripheral area of the retina, which surrounds the macula, contains photoreceptor cells called rods, which respond to lower light levels but are not color sensitive. The rods are responsible for peripheral vision and night vision.
The optic nerve carries signals generated by the photoreceptors (cones and rods). Each photoreceptor is joined to the optic nerve by a tiny nerve branch. The optic nerve is connected to nerve cells that carry signals to the vision center of the brain, where they are interpreted as visual images.
The optic nerve and the retina have a rich supply of blood vessels that carry blood and oxygen. Part of this supply of blood vessels comes from the choroid, which is the layer of blood vessels that lies between the retina and the outer white coat of the eye (the sclera). The central retinal artery (the other major source of blood to the retina) reaches the retina near the optic nerve and then branches out within the retina. Blood drains from the retina into branches of the central retinal vein. The central retinal vein exits the eye near the optic nerve.
The retina is a layer of tissue in the back of your eye that senses light and sends images to your brain. In the center of this nerve tissue is the macula. It provides the sharp, central vision needed for reading, driving and seeing fine detail.
Retinal disorders affect this vital tissue. They can affect your vision, and some can be serious enough to cause blindness. Examples are:
Retinal detachment – a medical emergency, when the retina is pulled away from the back of the eye
Macular pucker – scar tissue on the macula
Macular hole – a small break in the macula that usually happens to people over 60
Floaters – cobwebs or specks in your field of vision
When examining a person’s retina, a doctor puts drops in the eye to dilate the pupil. This allows the retina to be seen in much more detail with an ophthalmoscope.
Retinal disorders are often diagnosed and treated by an ophthalmologist (a medical doctor who specializes in diagnosing and treating eye disorders and doing eye surgery). Frequently, treatment is by an ophthalmologist who specializes in disorders of the retina.