{"id":8573,"date":"2020-10-11T18:42:27","date_gmt":"2020-10-11T18:42:27","guid":{"rendered":"https:\/\/www.optometrists.org\/?page_id=8573"},"modified":"2025-09-02T09:12:38","modified_gmt":"2025-09-02T09:12:38","slug":"how-does-the-eye-work","status":"publish","type":"page","link":"https:\/\/www.optometrists.org\/general-practice-optometry\/guide-to-eye-health\/how-does-the-eye-work\/","title":{"rendered":"How Does the Eye Work? Step-by-Step Explanation"},"content":{"rendered":"

Approximately 80 percent of everything we learn comes through our eyes \u2014 the question is, how?<\/b><\/h2>\n

The eye contains over two million working parts and is considered the second most complex organ in the body\u2014 the most complex is the brain.\u00a0<\/i><\/p>\n

The inner structures of the eye all work together to produce an image that your brain can understand.<\/p>\n

In order to produce a clear image, the eyes must complete a five step process:<\/p>\n

Step 1: Light enters the eye through the cornea<\/b><\/h2>\n

When we look at an object, the light that is reflected off of the object enters the eye through the clear front layer of the eye, called the cornea<\/b>. The cornea bends the light before it passes through a watery substance that fills the area behind the cornea, called the aqueous humor<\/b>.<\/p>\n

Step 2: The pupil adjusts in response to the light<\/b><\/h2>\n

The light continues to travel through the black opening in the center of the iris, called the pupil<\/b>. The iris <\/b>is the colorful part of your eye that gives it its blue, green, hazel, brown or dark appearance.<\/p>\n

The pupil then automatically gets bigger or smaller, depending on the intensity of the light.<\/p>\n

How does the pupil expand and contract?<\/b><\/p>\n

The iris is actually made up of muscles that expand and contract to control the pupil and adjust its size. So when you see your pupil getting bigger or smaller, it is really the iris that is controlling the pupil opening in response to the intensity of light entering the eye.<\/p>\n

Step 3: The lens focuses the light onto the retina<\/b><\/h2>\n

The light passes through the pupil to the lens <\/b>behind it. The lens adjusts its shape to bend and focus the light a second time, to ensure that you have a clear image of what you are looking at.<\/p>\n

At this point, the light has been bent twice\u2014 as it moved from the cornea through the lens, and then from the lens to the retina. This \u201cdouble bending\u201d has actually flipped the image upside down.<\/p>\n

If you suspect you have blurry vision or an eye condition, contact an eye doctor<\/a>\u00a0near you, who can diagnose and treat the condition.<\/strong><\/p>\n

SEE RELATED: <\/strong>Eye Anatomy: The Front of the Eye<\/a><\/p>\n\n\t

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Find an eye doctor near you<\/h3>\n\t\t\n\t
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