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Home » Eye Care Services » Your Eye Health » How the Eye Works

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!

Dear Valued Patient:

We plan to re-open on May 20, 2020 to a limited schedule by appointment only—please set appointment online or call or email first.

We look forward to see you again soon!  We place the highest priority on the health and safety of our patients and our eye care staff.  Please read below:

Please read the following carefully to prepare for your visit to our office. We are implementing many new and more stringent procedures to ensure the health and safety of our patients and eye care personnel based on guidelines from the Alameda County Health Department and the CDC to help prevent the spread of COVID-19. During this time we are requiring the following for every patient and in-office encounter:

+We are starting with a limited schedule of appointments for better social distancing and for the safety of our patients (thank you in advance for your patience and understanding).

+All visits are by appointment only, there are no walk-in visits available

+All patients are required to wear their own personal mask before entering the office

+All patients are required to check in over the phone before their appointment

+Insurance coverage verifications must be taken care of before entering office for appointment

+Patient will wait outside in car until notified by text or email when they can come in for their appointment, upon entering, patient’s temperature will be taken and their hands sanitized with alcohol cleaner

+There will be no waiting area in the office, patient will be seen right away-please be on time

+Family or caregivers will need to wait outside in the car, as we will only allow patient to enter office.  Verbal consent for minors is acceptable. Updates will be given family or caregiver over the phone as needed.

+All glasses, contact lens orders will be by curb side pick up only—please call or email and we can help you set up a time to pick up your eye wear safely, maintaining social distancing

Our doctors and staff will increase our cleaning and sanitizing protocols:

+We have the latest HEPA air filters with UVC light disinfection to destroy bacteria and viruses

+Wearing protective face shields and surgical masks and medical grade disposable gloves

+All exam equipment and every surface is sanitized fully with hospital grade sanitizer after each patient encounter

+We have a new safe system of disinfection for all frames which have been touched or tried

+We screen all patients by phone to assure they have been healthy prior to their appointment

+All staff and doctors have passed additional training in more stringent sanitizing protocol

Thank you for your patience and compliance to these new and required guidelines. Our goal is to take care of your eye care needs while keeping you and your family healthy. We also want to help our community overcome this pandemic.

We will get through this together.

Please let us know if you have any questions or need more immediate assistance. 

You can set up a future appointment online at EyeCareDrLee.com or send an email to EyeCareDrLee@gmail.com or DrLeongOK@gmail.com  or call 510-668-0877

Please stay safe and stay healthy.

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Stay up to date on our COVID-19 pandamic protocols Read Our Blog Post…

Our office continues to monitor the local health announcements on a daily basis. Optometry is an essential service and we will open to new health guidelines to help our patients while keeping everyone healthy. Please read our blog updates for our open date and new safety guidelines. Let us know if you have any questions or immediate eye care needs. Need contact lenses? Let us know, as we can send orders to you with free shipping.
We are responding faster to direct email:

eyecareDrLee@gmail.com

drLeongOK@gmail.com (for ortho-k)

Thank you, stay safe and stay healthy.

COVID-19 guidelines from CDC: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention-H.pdf