A Look at the Human Eye

Human eye

How the Human Eye Works

Seeing is possible thanks to a complicated series of events that start in the eyes and end in the brain. The entire process happens almost instantaneously and is only successful if every part of your visual system works properly.

It All Starts with the Cornea

Your cornea, a clear, rounded layer of tissue that covers your pupil and iris, helps light reach your eyes by bending the rays as they enter your pupils.

The iris and pupil work together to let light into the eye. Have you noticed that your pupils look bigger when the light is dim? Tiny muscles in the iris make the pupil bigger when it's harder to see, allowing more light to enter your eyes. The muscles shrink the size of your pupils when it's bright outside or inside.

The Lens Is Essential for a Clear Picture

Light rays pass through the lens and the vitreous humor after entering the eye. The lens is a transparent disc located inside the eye under the iris and pupil, while the vitreous is the clear gel that gives the eye its shape.

The muscles that control the shape of the lens relax, causing the lens to flatten when you look at an object in the distance. The opposite happens when you look at something nearby. The muscles contract, thickening the lens. The ability of the lens to change shape allows you to shift your focus from near to far objects and back again.

The lens focuses light rays on the retina in the back of the eye. If your eyeball is too long, the rays will focus in front of the retina, causing myopia, or nearsightedness. If you're nearsighted, close objects are easy to see, while everything in the distance looks blurry.

Hyperopia, or farsightedness, occurs when your eyeball is too short. Light rays focus beyond your retina and make your near vision blurry.

As you get older, the lenses of your eyes become less flexible. The loss of flexibility affects your ability to see near objects clearly. This condition, called presbyopia, usually begins in your early- to mid-forties, according to the American Optometric Association. Fortunately, a pair of reading glasses will make it much easier to read a book or thread a needle.

The Retina Transforms Light Rays

The retina covers the back of the eye and contains two types of photoreceptor cells. The rods, found in the outer part of the retina, are essential for side vision and help you see in dim light. Cones, the other type of photoreceptor cells, are located in the macula, the center part of the retina. Cones are needed for color vision and also help you see fine details easily.

The retina turns light rays into electrical impulses, then sends the impulses to the occipital lobe of the brain through the optic nerve. Problems with your retinas or optic nerve can affect your vision.

If you have macular degeneration, a common age-related eye condition, your central vision may be blurry or you may notice blank spots in the middle part of your vision. Increased eye pressure due to glaucoma can damage your optic nerve, causing partial or total loss of vision.

How Your Brain Helps You See

The visual cortex in the brain's occipital lobe serves as the vision command center. The cortex processes and stores images and helps you make sense of what you see. Thanks to your brain, you can recognize faces, colors, letters, and shapes. You can also see fine details, avoid obstacles, keep your balance, predict the speed of moving objects, remember the things you've seen in the past, and easily recall information after reading it.

Your brain also controls the muscles that move your eyes and turns the slightly different information received from each of your eyes into one clear image.

If a stroke, tumor, infection, disease, or head trauma injures the brain, your vision and your ability to understand what you see can be temporarily or permanently affected.

Annual visits to the optometrist help you ensure that every part of your visual system is working properly. Contact our office if you're ready to schedule your next eye exam.

Sources:

American Optometric Association: Adult Vision: 41 - 60 Years of Age

National Eye Institute: How the Eyes Work

American Optometric Association: How Your Eyes Work

American Macular Degeneration Foundation: How the Eye Works as a Camera

American Academy of Ophthalmology: Eye Anatomy: Parts of the Eye and How We See, 3/9/21

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Hours of Operation

We are closed for lunch daily from 12:00 PM to 1:00 PM

Brier Creek Vision Care

Monday:

8:00 AM - 5:00 PM

Tuesday:

8:00 AM - 5:00 PM

Wednesday:

8:00 AM - 5:00 PM

Thursday:

8:00 AM - 5:00 PM

Friday:

8:00 AM - 5:00 PM

Saturday:

Closed

Sunday:

Closed

Testimonial

  • "Excellent office. Staff is helpful and polite when dealing with my special needs child. They understand when he needs break and how to redirect to another technique to achieve goal. Would highly recommend to others!"
    Jennifer, Raleigh, NC
  • "I needed an eye doctor to see me for my concussion issue that effected my eyesight. There isn't many who are able to assess. Dr. Durham knew just how to work with my case in a gentle manner to help keep me calm. I finally have hope for healing now."
    Elizabeth 3/15/19 - Answer to Prayer
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    Elizabeth 3/11/19
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    I have already told my friends about my visit to the future."
    Patricia 2/24/19 - Everything was perfect.
  • "My daughter and I have have had great experiences at Brier Creek Vision! Dr. N. Is fantastic!! The office staff is super friendly, accommodating and very pleasurable to work with. Eye glass frames are plentiful and the opticians are helpful, suggestive and patient! Thanks to everyone for making all of visits wonderful!!"
    Cynthia 2/14/19 – Great Experience
  • "Dr Nakagawara is open, friendly and extremely knowledgeable. Karim Glover in the optical dispensary took great care in explaining and helping me to get great value on a new set of prescription sunglasses that will do much more than my previous set. Extremely happy.
    Loved the Optician!"
    Thomas 2/22/19 - Great Doctors and Team...
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    Helen 2/21/19 - Excellent care
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    Kris 1/31/19 - Amazing Experience
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    Melissa 1/31/19 - Recommend
  • "I always have the best visit at Brier Creek Vision. My Doctor, Esther Nakagawara, is the best at what she does! She handles the procedures with care, caution and concern, explains well and has the best solutions to keep your eyes healthy. The staff is accommodating, patient and very kind to everyone; they never mind answering questions. The opticians are helpful in assisting with the selection of eyecare that looks good and works the best for you. I have told many people about my positive experiences at Brier Creek Vision and recommended this office as well."
    Kailah 1/30/19 - The Best in Eyeccare!!
  • "My family and I have been patients of Brier Creek Vision for 2 years. Dr. Nakagawara is a very caring and skilled OD who communicates, teaches and plans well. The staff and optometrists are inviting, knowledgeable and very helpful. We have recommended BCV to all our friends and family!"
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