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How the Eye Works

To understand how the human eye works, first imagine a photographic camera—since cameras were developed very much with the human eye in mind.

How do we see what we see?

eye diagramLight reflects off of objects and enters the eyeball through a transparent layer of tissue at the front of the eye called the cornea. The cornea accepts widely divergent light rays and bends them through the pupil—the dark opening in the center of the colored portion of the eye.

The pupil appears to expand or contract automatically based on the intensity of the light entering the eye. In truth, this action is controlled by the iris—a ring of muscles within the colored portion of the eye that adjusts the pupil opening based on the intensity of light. (So when a pupil appears to expand or contract, it is actually the iris doing its job.)

The adjusted light passes through the lens of the eye. Located behind the pupil, the lens automatically adjusts the path of the light and brings it into sharp focus onto the receiving area at back of the eye—the retina.

An amazing membrane full of photoreceptors (a.k.a. the “rods and cones”), the retina converts the light rays into electrical impulses. These then travel through the optic nerve at the back of the eye to the brain, where an image is finally perceived.

A delicate system, subject to flaws.

It’s easy to see that a slight alteration in any aspect of how the human eye works—the shape of the eyeball, the cornea’s health, lens shape and curvature, retina problems—can cause the eye to produce fuzzy or blurred vision. That is why many people need vision correction. Eyeglasses and contact lenses help the light focus images correctly on the retina and allow people to see clearly.

In effect, a lens is put in front of the eye to make up for any deficiencies in the complex vision process.

The main parts of the human eye include:

  • Cornea: transparent tissue covering the front of the eye that lets light travel through
  • Iris: a ring of muscles in the colored part of the eye that controls the size of the pupil
  • Pupil: an opening in the center of the iris that changes size to control how much light is entering the eye.
  • Sclera: the white part of the eye that is composed of fibrous tissue that protects the inner workings of the eye
  • Lens: located directly behind the pupil, it focuses light rays onto the retina
  • Retina: membrane at the back of the eye that changes light into nerve signals
  • Rods and cones: special cells used by the retina to process light
  • Fovea: a tiny spot in the center of the retina that contains only cone cells. It allows us to see things sharply.
  • Optic Nerve: a bundle of nerve fibers that carries messages from the eyes to the brain
  • Macula: a small and highly sensitive part of the retina responsible for central vision, which allows a person to see shapes, colors, and details clearly and sharply.

 

Special thanks to the EyeGlass Guide, for informational material that aided in the creation of this website. Visit the EyeGlass Guide today!

In an effort to further protect our patients and staff, we are taking the following precautions at our office:

When you arrive in the office for your appointment:

  1. The door will remain locked and open only for patients that have been initially screened
  2. Careful Screening:  All persons entering the office will be screened for symptoms of COVID-19 by 1) being asked a series of screening questions and 2) their temperature will be taken before entering the office.  If the patient's temperature is greater or equal to 100.4 degrees F (38 degrees C), that person will be denied entrance and asked to see their primary care physician.
  3. No additional family, friends, etc will be allowed to accompany the patient into the office
    1. *Exception: children and others requiring assistance - 1 single parent or accompanied guardian allowed
  4. We ask that you please wear cloth or medical MASKS when entering our office. A mask will be required for entry through the door.
  5.  We will be implementing a *$50 “No Show Fee”* for no shows or cancellations if we are not notified at least 24 hours prior to your scheduled appointment.

Safety and Sanitization Precautions:

Frame Selections, Adjustments, Repairs and Dispensing:

 

Although there may be some changes to your normal visit to our office, we assure you that we are doing our best to follow all CDC, California Department of Public Health, California Optometric Association and local public health guidelines to keep our patients, staff and community safe without compromising our standard of excellence and quality during this time.

We ask that you all are mindful of the following precautions. We are all in this together. We look forward to SEEing you all soon!

Aloha Family Optometric Team