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Home » 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 Richie Eye Clinic & LASIK Center Family and Friends,

As we head into the Holiday Season and the New Year, I have some news to share.

As many of you know, we have added some new doctors to our team in the last couple of years. Dr. Josh Spedding OD, our new Optometrist, joined us last summer and is currently seeing patients in both our Northfield and Faribault offices. We are thrilled to have Dr. Spedding on our team and welcome him and his family to the area.

Dr. Cory Miller, MD joined us in 2021 and we welcomed Dr. Mike Reinsbach, MD to our team this past summer. Both are Board Certified Ophthalmologists and skilled surgeons specializing in High Technology Cataract Surgery with Advanced Lens Implants, LASIK, Retinal injections, MIGS Surgery for Glaucoma, as well as the usual medical and surgical management of eye disease.

With the addition of these high performing providers, I am transitioning my role in 2023 to concentrate on Practice Development while continuing to serve as the Medical Director overseeing our practice protocols and procedures. Dr. Miller and Dr. Reinsbach will be assuming my day-to-day patient care duties.

I have done my best over the past several months to tell everyone of this transition plan while personally introducing Dr. Miller and Dr. Reinsbach; please accept my apologies if I missed any of you during this time.

Rest assured, we will continue our commitment to providing cutting edge care. Starting in 2023 look for Dropless Cataract Surgery, Light-Adjustable Lens Implants, and so much more…

Thank you for the Trust and Confidence you have shown me over the past 32 years. Please feel free to call us at (507) 332-9900 for questions, concerns, or clarification.

Sincerely,

Mike Richie, MD

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