Which part of the eye is responsible for protecting the inner structures?

The sclera is a tough, outer layer of the eye that serves the important function of protecting the inner structures. It is often referred to as the "white of the eye" and provides not only a protective barrier but also maintains the shape of the eye. This tough connective tissue supports and protects the more delicate internal components of the eye, such as the retina and the choroid.

The other structures like the lens, pupil, and iris have specific roles in vision and the eye’s functionality. The lens focuses light onto the retina, the pupil regulates the amount of light entering the eye, and the iris controls the size of the pupil and gives the eye its color. While all these components are essential to the overall function of the eye, they do not primarily serve the protective role that the sclera does. The sclera’s robust nature is critical for safeguarding the eye's internal mechanisms from injury and environmental hazards.