Basic Eye Information

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Is the eye just like a camera?

Although often compared to a camera, the eye is far more complicated and complex. It not only focuses and takes “pictures” but it also tracks and follows the target then processes this information seamlessly with the brain which ultimately allows us to be conscious of what we “see”.

Why do we say that our eyes are so complex?

Our eyes are indeed a very complex sensory organ that is an extremely important part of what we call the visual system. In order for us to “see”, first there must be light rays emitted from or be reflected off of a target. As these light rays enter and pass through the eye, an image is focused by the cornea and lens (and glasses if worn) and projected onto the retina. The retina is at the back of eye and consists of millions of light receptive cells that convert these focused light rays into electrical signals that are transmitted through a multilayered system into our brain. Once the brain receives and processes these signals, we perceive an image. It is at that moment that vision has occurred and we say “I see”.

What does that mean to have your visual acuity measured?

Visual acuity testing is a measurement of a person’s ability to see in sharp, clear, and fine detail. Visual acuity expressed as “20/20” is what is referred to as normal vision.

What are the four ways one commonly evaluates our visual abilities?

The 4 parts of the visual system that are commonly evaluated are central vision, peripheral vision,
3-D vision or depth perception, and color vision.

What is central vision?

Central vision is the ability to clearly see objects at which one is looking.

What is peripheral vision?

Peripheral vision is the ability to see shapes and forms that surround the central vision target. Peripheral vision does not give us a detailed vision.

What is 3-D vision?

3-D vision or depth perception is the ability of our two eyes to view one object from slightly different angles which the brain blends these two views giving us a perception of dimension and position in space of the object at which we are looking.

What is color vision?

There are light receptive cells in our retina that are called cones. In the normal eye there are 3 different kinds of cones, each perceiving or responding to different wave lengths of light. Typically we refer to these as red, green, and blue cones. It is through the variable stimulation of these cones that allow the human to differentiate over a million shades of color.
Additional Information

Why does the eye have its own field of medicine?

With so many vital components of the eye and so many aspects to visual ability, it is no wonder that so much effort and so many different kinds of professionals are involved in preserving eyesight and maintaining eye health.

Anatomy information may be obtained through these links: