The cornea is the clear window in the front of our eye that lets light inside.  If you were to touch the “colored part of your eye” with your finger, you’d be touching the cornea.  The cornea is an extremely important part of vision – it acts as a fixed lens and actually provides the majority of the focusing power of the eye.  Opacities of the cornea, from past infections or trauma, can severely limit fine visual acuity.  The cornea has 5 distinct structural layers.  The surface layer is called the epithelium.  This layer is very thin and can scratch off if a foreign body gets in the eye. This is called a corneal abrasion.  The middle layer is called the stroma – if an injury gets into this middle layer, scarring can form with possible visual consequences.  The inside layer of the cornea is very thin and called the endothelium.  This inner layer is important as the cells in this layer contain “pumps” that suck fluid out of the cornea. The cornea is clear because it is relatively dehydrated compared to other tissues in the body. If the pump mechanism of the inner cornea is injured or abnormal (such as in Fuchs’ dystrophy or after a traumatic cataract surgery) the cornea can become too wet and cloudy.

Dr. Timothy Root is a practicing ophthalmologist and cataract surgeon in Daytona Beach, Florida. His books, video lectures, and training resources can be found at:


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