Advanced Eye and Laser Center of California, Inc. | Dr. Paul Huynh
Monday, August 25, 2008
How the Eye Works
The popular analogy for how our eyes work is a camera, and it’s a good analogy. Cameras have a viewfinder, adjustable lens and film, all lined up one behind the other in a closed-off structure. The eye has structures that correspond to each of those.
The cornea is like the viewfinder – we look out through it to see and to decide what to focus on. The cornea has other functions though, as it also allows light through to the lens, whereas light goes directly to a camera lens. The cornea and the lens both bend that incoming light to focus it on the retina. It also protects the eye by being fairly thick and tough, and by being covered in moisturizing fluid which we continually spread over it by blinking.
The adjustable lens is behind the iris (colored part), and is controlled by little muscles. It changes its curvature to focus clearly at near, intermediate, and far distances, just as a camera lens can be set to give a clear picture at any given distance. (In many modern cameras, and in all simple cameras, this is done automatically, but in older or more sophisticated cameras, it is done manually for greater precision.) In the eye, this adjustability is called accommodation – the lens accommodates itself to varying distances.
The retina is at the back of the eye and corresponds to the camera film. Light-sensitive cells receive images brought in by light rays and convert that image information into nerve energy. A large nerve connects the retina to the brain.
The brain functions like a dark room, making the nerve energy into an intelligible picture and naming it for us. Our modern digital cameras don’t need a dark room in the sense of that literally dark room where negatives were developed and prints made. But they perform the same function using electronics.
You can read more detail on our How the Eye Works page.
If you are nearsighted or farsighted, Dr. Huynh can correct that by changing the cornea’s curvature in a LASIK surgery. If your lens develops cataracts, he can replace it with an implanted artificial lens. He can also do this to correct “middle-aged” vision (presbyopia).
To schedule a personal consultation with Dr. Huynh and learn more about your eyes and how your vision could be improved, please call or email our San Diego office today.
The cornea is like the viewfinder – we look out through it to see and to decide what to focus on. The cornea has other functions though, as it also allows light through to the lens, whereas light goes directly to a camera lens. The cornea and the lens both bend that incoming light to focus it on the retina. It also protects the eye by being fairly thick and tough, and by being covered in moisturizing fluid which we continually spread over it by blinking.
The adjustable lens is behind the iris (colored part), and is controlled by little muscles. It changes its curvature to focus clearly at near, intermediate, and far distances, just as a camera lens can be set to give a clear picture at any given distance. (In many modern cameras, and in all simple cameras, this is done automatically, but in older or more sophisticated cameras, it is done manually for greater precision.) In the eye, this adjustability is called accommodation – the lens accommodates itself to varying distances.
The retina is at the back of the eye and corresponds to the camera film. Light-sensitive cells receive images brought in by light rays and convert that image information into nerve energy. A large nerve connects the retina to the brain.
The brain functions like a dark room, making the nerve energy into an intelligible picture and naming it for us. Our modern digital cameras don’t need a dark room in the sense of that literally dark room where negatives were developed and prints made. But they perform the same function using electronics.
You can read more detail on our How the Eye Works page.
If you are nearsighted or farsighted, Dr. Huynh can correct that by changing the cornea’s curvature in a LASIK surgery. If your lens develops cataracts, he can replace it with an implanted artificial lens. He can also do this to correct “middle-aged” vision (presbyopia).
To schedule a personal consultation with Dr. Huynh and learn more about your eyes and how your vision could be improved, please call or email our San Diego office today.
posted by Patti at 11:03 AM
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