Transparent and dished area of eye called Cornea. It is membrane that protect retina and make optical refraction. There are no vain so it is transparent. It feeds and covers metabolic needs with limbus’s vain. It is made of three layers;

• Outer layer is called regenerate epithelium is carries lipophilic character.
• Mid-layer is called stroma is carries hydrophilic character that is convenient for bacteria, virus, etc.
• Internal layer is called non-regenerate endothelium is contact with aqueous.

The spot that cornea and sclera connected is called limbus. It is humidity and oxygen needs provide by aqueous layer. Cornea makes optical refraction and it give shape to the eye. Cornea should be wet all the time. Tear film epithelium and aqueous helps to keep endothelium wet. These liquids also helps to provide oxygen and other needs.