Cornea

Cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. The cornea, with the anterior chamber and lens, refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power.

Cornea

Vertical section of human cornea

SD-OCT Corneal Cross-Section

Anatomy

The human cornea has a diameter of about 11.5 mm and a thickness of 0.5–0.6 mm in the center and 0.6–0.8 mm at the periphery. Transparency, avascularity, the presence of immature resident immune cells, and immunologic privilege makes the cornea a very special tissue.

Function

The cornea contributes to the eye's ability to focus by refracting light as it enters the eye. The cornea is responsible for 65-75% of the eye's total focusing power. When light strikes the cornea, it bends--or refracts--the incoming light onto the lens. The lens further refocuses that light onto the retina, a layer of light sensing cells lining the back of the eye.

Diseases and disorders

There are many diseases that can affect the cornea, including keratitis, keratoconus, corneal ulcer, Fuchs' dystrophy, and Lattice dystrophy. These diseases can cause pain, blurred vision, tearing, redness, and extreme sensitivity to light.

Treatment

Treatment for corneal disease can take many forms, depending on the underlying problem. Some conditions resolve with the use of medicated eye drops. When the disease is more deeply seated, a corneal transplant may be needed.

Images

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  Human eye with limbal ring, anterior view
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  Cornea
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  Cornea

See also

• Eye
• Human eye
• Ophthalmology