Which layer of the eye is primarily responsible for protecting the eyeball?

The sclera is the layer of the eye primarily responsible for protecting the eyeball. It is a tough, white outer layer that provides structural support and protection to the internal components of the eye. The sclera helps to maintain the shape of the eyeball and acts as an anchoring point for the muscles that control eye movement.

While the cornea also plays a protective role by serving as the first barrier that light encounters on its way into the eye, its primary function is to refract light. The iris, on the other hand, is primarily responsible for controlling the amount of light that enters the eye by adjusting the size of the pupil. The retina is the innermost layer and is responsible for converting light into neural signals for vision, but it does not contribute to the structural protection of the eye itself. Therefore, the sclera stands out as the key layer dedicated to protecting the eyeball.