Going to the movies…
In this particular episode of Ask an Eye Doc, you will learn:
- Where the retina is located within the eye
- What the retina does
- What are photoreceptors (rods & cones)
- How your eye is like a movie theater
- How your eye is like a camera
- About the macula and the peripheral retina
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For you readers out there, here’s the answer in written form:
What is the retina?
This is an important question for you to understand before you learn more about certain eye conditions such as retinal detachment, macular degeneration, and diabetic eye disease. First, let’s talk about where the retina is, and then we’ll discuss what it does.
Many people don’t realize the eye is actually a hollow ball. The retina is a very thin layer that lines the inside of that ball. Think if your eye were a room, the retina would be the wallpaper. When I show retinal photos to my patients, I like to describe the retina as the “inside back lining of the eye.”
The retina is made up of specialized nerve cells called photoreceptors. These cells detect light and send that information to the brain. In other words, the retina is what allows you to see light. Without it, you would be blind.
When light enters the eye through the cornea and crystalline lens, it is projected onto the retina much like a movie is projected onto a screen at a movie theater. The retina also functions like camera film. If the film is bad or missing, the image quality is degraded or missing.
Rods and cones
Different parts of the retina correspond to different parts of your vision. For example, the central part of the retina is called the macula, which corresponds to your straight-ahead vision. The macula contains a high concentration of photoreceptors called cones, which account for your ability to see fine detail as well as color vision.
The peripheral retina corresponds to your side vision and has photoreceptors called rods, which detect shades of black and white as well as motion. This part of your retina is better at seeing in low light conditions. (For a fun trick, try stepping into a dark room and see if you’re using your central vision or your peripheral vision more — hint, you should find that you’re relying more on your side vision).
So now you know a little more about the retina!