Cornea: Definition & Function

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  • 0:02 Structure of the Eye
  • 1:05 Disorders of the Cornea
  • 2:16 Corneal Transplant
  • 2:53 Lesson Summary
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Lesson Transcript
Instructor: Betsy Chesnutt

Betsy teaches college physics, biology, and engineering and has a Ph.D. in Biomedical Engineering

One of the most important structures in your eye is the cornea. In this lesson, you'll learn what the cornea is and how it helps you to see. You'll also learn about some common disorders of the cornea and how they are treated.

Structure of the Eye

As you are reading this right now, stop for a minute and think about how it is possible for you to actually see the words. Your eyes are very complex organs made up of many structures that all have to work together to allow you to have clear vision. One of the most important structures in your eye is the cornea. The cornea is a thin, clear membrane that covers the outer part of the front of the eyeball. It's made primarily of a protein called collagen, which is very tough and strong. Because it's so tough and strong, it protects the delicate structures inside the eye from damage.

In addition to protecting the eye, the cornea has another very important function for your vision. When you look at something, light goes into your eye and the cornea is the first thing it passes through. Since the cornea is a curved surface, it acts like a lens and begins to focus the light. The light then goes through the pupil of your eye and is further focused by the lens so that a clear, sharp image can be formed on the retina at the back of the eye.

Disorders of the Cornea

The most common problem you can have with your cornea is a corneal abrasion. This occurs when the cornea becomes scratched due to trauma like a scratch from your fingernail or a branch. It can also happen if you wear contact lenses when the lens is removed or if dirt or other abrasive particles get trapped underneath the lens. Although corneal abrasions can be painful, they're easily treated with eyedrops and/or a soft contact lens that can be placed in your eye to protect the cornea until it heals.

Corneal dystrophy occurs when substances other than collagen begin to build up in your cornea and make your vision cloudy. This is a hereditary disorder that gets worse with increasing age. It's usually treated by performing a corneal transplant, where a donated cornea is transplanted into your eye to replace your cloudy cornea.

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