The first structure we will explore is the Cornea, which is the clear front surface of the eye, its role is like a protective shield that keeps away dust, germs, and other matters that might enter the eye, it also serves as a refractive medium to refract light into the eye. The cornea does not have blood vessels to provided nutrients instead it receives it from the tears and aqueous humor that is produced in the eye.
The cornea has five basic layers:
The Epithelium, it is the front surface and acts as a barrier to protect the eye and also a provide a smooth surface for tears.
Bowman's Layer, lies right below the epithelium, It is comprised of strong collagen fibers and helps the cornea keep its shape.
Stroma - composed of collagen fibers and keratocytes, it provides the majority of the cornea about 90 percent. It consists primarily of 78% water and 16% collagen that give the cornea its strength, elasticity, and form.
Descemet's membrane is composed of collagen fibers (different from those of the stroma) and is made by the endothelial cells that lie below it, This layer is important for the health of endothelial cells.
Endothelium- the innermost layer of the cornea, this single layer of cells is located between the stroma and the aqueous humor. Because the stroma tends to absorb water, the endothelium's primary task is to pump excess water out of the stroma. Without this pumping action, the stroma would swell with water, become hazy, and ultimately opaque.
.. on the next part we will discuss the Iris.
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Until next time cheers!