When looking at the human eye visually, you can see the black, slightly rounded portion, and the white portion around it. The black part, commonly referred to as the black eye, is where the cornea is located. The cornea is transparent and is often mistaken for black because it is seen through the cornea and is followed by the brownish-black iris. The cornea is surrounded by white sclera and a translucent conjunctiva. The cornea is transversely elliptical in shape, with an average diameter of about 11-12 mm transversely and 10-11 mm longitudinally, with the cornea being slightly smaller in women than in men. The cornea is normally transparent, but when inflammation occurs, the cornea becomes grayish-white or porcelain-white opaque, and that is the diseased cornea.