Translations:The Eye and Retina/3/en

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The Anatomy of the Eye

The Cornea

The cornea is the transparent surface of the eye which covers the pupil and iris. The cornea functions not only to protect the eye, but it is also the first refractive surface that light goes through on its way to the retina. A healthy cornea contains no blood vessels, so it takes in oxygen from the air to keep it healthy. When the cornea is deprived of oxygen for long periods of time, e.g. overwearing of contact lenses, the body will try to compensate for this by growing blood vessels into the cornea. This can increase the chance of negative immune system responses in the future (causing redness, pain, swelling and eventually damaging the cornea permanently).

The cornea consists of five layers, the epithelium, Bowman's layer, the stroma, Descemet's membrane, and the corneal endothelium. The epithelium is responsible for protecting the rest of the cornea, as is Bowman's layer. The stroma makes up approximately 90% of the thickness of the cornea while remaining transparent. Descemet's Membrane and the corneal endothelium function to control fluid and nutrient flow between the cornea and the rest of the eye.[1]

  1. Binder, P. S. et al. (July 1991) High-voltage electron microscopy of normal human cornea. Invest. Ophthalmol. Vis. Sci. 32 (8): 2234-43