About The Retina
Understanding the Retina
What is the retina?
The retina is the back surface inside the eyeball, opposite the lens. It contains millions of light sensitive cells, called rods and cones. An image projected by the lens onto the retina is sensed by the rods and cones as different intensities of light and different colors. When light hits rods or cones, a biochemical reaction occurs, which initiates the transmission of signals along nerve cells to the brain, with information about light, color and position in the retina. In the brain, the signals from throughout the retina are assembled into the experience of seeing what is before us.
Other important definitions for understanding the retina:
What is the macula?
The central portion of the retina directly opposite the lens, is called the macula. It is rich in cones, the cells, which enable us to see fine detail and color. There are three classes of cones, each most sensitive to a different color: red, green or blue.
What is the fovea?
At the center of the macula is very small area called the fovea. Cones are most concentrated in the fovea. Despite its small size, relative to the rest of the retina, the fovea is very important for our ability to see fine detail and color.
Common Retina Problems:
- Diabetic Retinopathy - The deterioration of retinal blood vessles, called diabetic retinopathy, can lead to vision loss. Although considered one disease, there are many types of diabetic retinopathy.
- Macular Degeneration - Age-related macular degeneration (AMD) is a deterioration or breakdown of the eye's macula often related to the aging eye.
- Macular Edema - Macular edema refers to fluid or swelling of the retinal tissues that make up the macula. It may also include fluid that collects underneath the macula.
- Macular Hole - A small break in the macula, located in the center of the eye's light-sensitive tissue called the retina.
- Flashes and Floaters - Floaters are spots or lines that seem to float in a person's field of vision. The affected person may see these accompanied by flashes of light coming from the side of the eye.
- Retinal Detachment - A retinal detachment is a condition where the tissues of the retina separate from the back of the eye.
- Sickle Cell Disease - Sickle cell disease, like diabetes, can cause new blood vessels to grow within the eye. Neovascularization or new blood vessels is the most serious problem secondary to Sickle retinopathy.
- MACULAR PUCKER (Pre-retinal Fibrosis) - A thin layer of fibrous tissue has formed and rests on the retinal surface. The scar tissue contracts and causes wrinkling of the normally flat retina. Macular pucker is analogous to cellophane wrap that has been wrinkled. For this reason, macular pucker has also been called cellophane maculopathy.