A beautiful rainbow, a sunset over the ocean, the smile of a child, and so many other breathless experiences would pale and darken were it not for the human eye, which allow us to experience life in color. The eye is the body’s camera, and almost every memory we have is freeze framed inside our brain’s database. Even though most of us know this, human sight is even more fascinating once understanding the process that makes sight possible.

Human Sight Elements

The human eye is a fascinating instrument. Understanding human eyesight begins with the cornea. The cornea is found at the front of the eye and focuses on the light itself. Just behind the cornea is the iris of the eye. The iris opens to create the pupil. The pupil acts as an adjustable camera lens, widening or reducing in shape, dependent on how much light is entering the eye.

There is then a fluid, behind the eye, the aqueous humor. This fluid is between the cornea and iris, and acts as a sort of liquid buffer zone, filling space between these to two needed parts. Behind the pupil is a colorless substance. This chrystalline lens is surrounded by muscle tissue. The muscles have two functions. First they hold the chrysalline lens in place, and second, they allow the lens to receive light.


Eye Muscles And Vision

The chrystalline lens can be thought of as the contact lens for the body. When muscles relax the lens is stretched a bit and flattens as a result. This allows for seeing things in the distance. When eye muscles contract, the lens becomes a bit thicker, allowing for close-up vision.

Beyond this is a substance similar to jelly that fills the chamber of the eye. This is called the vitreous humor. Behind the vitreous humor is the retina. The retina consists of three intricate layers. The first layer is the sclera. The sclera is responsible for the white color of the eyeball.

Behind the sclera is the choroid. The choroid can be thought of as eye’s life giving force. The choroid is made up of blood vessels and supplies the eye with nutrients and oxygen. It also removes all things in the eye that are potential problems. It cleans and removes waste from the eye.

The Eye’s Camera Sensors

The retina is also made of millions of cells whose function is sensing light. These rods and cones are the light and dark, color, and vision sharpness and clarity tool for the body’s eye. Like a camera, these rods sense poor light, which allow for adjustments to the human eye.

Cones, on the other hand, sense color and detail contrasts. Cones sit directly behind the retina. Once light is sensed in the rods and cones it is transferred into an electric signal. This optic energy signal is picked up by the optic nerve. This messenger transmits the signal directly to brain, which then converts signals into images the eyes see. This miraculous process is responsible for all the life in living color that humans experience.


Barry Trent is a guest blogger.  His interest in the human eye led him to many eye doctor websites in Tucson, AZ.

image soruce: pascoeye.com

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