Final answer:
The central, transparent part of the eye's outer coat covering the iris and pupil is known as the cornea. This structure is vital for allowing light to enter and focusing it onto the retina to facilitate vision.
Step-by-step explanation:
The central, transparent part of the outer coat of the eye that covers the iris and pupil is called the cornea. The cornea is part of the fibrous tunic, the outermost layer of the eye, which also includes the white sclera. The cornea serves several important functions; it allows light to enter the eye and is pivotal in focusing that light onto the retina to produce clear images. It acts in conjunction with the lens to refract and focus light, and together with the sclera, it helps to protect the inner contents of the eyeball.
The middle layer of the eye, called the vascular tunic, contains the iris, a smooth muscle that regulates the size of the pupil and thus controls the amount of light that enters the eye. The innermost layer is the neural tunic, or retina, which contains the photoreceptive cells responsible for converting light into neural signals for the brain to interpret as visual images.