Which clear tissue covers the front of the eye?

The cornea is the clear, dome-shaped tissue that covers the front part of the eye. It serves several essential functions, including protecting the inner components of the eye and helping to focus light as it enters. The transparency of the cornea is crucial for clear vision, as any opacification can result in vision impairment. The cornea contains no blood vessels; instead, it receives nutrients through the tears and the aqueous humor, which maintains its clarity and health.

In contrast, the iris is the colored part of the eye that controls the size of the pupil and thus regulates the amount of light entering the eye. The sclera is the white outer layer of the eye that provides structure and protection but does not cover the front portion. Finally, the vitreous humor is a gel-like substance that fills the space behind the lens and helps maintain the eye's shape, but it is not a tissue that covers the eye.