What part of the eye helps protect it from foreign objects?

The conjunctiva is a thin, transparent membrane that covers the front part of the eyeball, up to the edge of the cornea, and lines the inner surface of the eyelids. Its primary function is to provide a protective barrier against foreign particles, dust, and microorganisms that could cause damage or infection to the eye. Additionally, it helps keep the eye moist by producing mucus and tears, further enhancing its protective role. This is crucial for maintaining overall eye health and clear vision.

While the sclera offers structural support and some protection as the white outer layer of the eye, it does not have the same direct role in safeguarding against foreign objects as the conjunctiva. The cornea is the transparent front part of the eye that also aids in protecting the eye but primarily focuses on refracting light rather than protecting against debris. The iris, which is responsible for controlling the amount of light that enters the eye, does not contribute to physical protection against foreign objects. Therefore, the conjunctiva is the most accurate answer as it is specifically designed to defend the eye from external threats.