What is conjunctiva?

Conjunctiva refers to the thin, transparent membrane that covers the outer surface of the eyeball, specifically the part that is not covered by the cornea. It extends from the edge of the cornea to the inner surface of the eyelids. This structure plays a crucial role in protecting and lubricating the eye by producing mucus and tears, which help to keep the surface of the eye moist and free from debris. Its clear and delicate nature allows light to pass through while still providing a barrier against foreign particles and microorganisms.

The other options describe different anatomical structures of the eye. The retina is responsible for converting light into neural signals but is located at the back of the eye, disconnected from the conjunctiva. The colored part of the eye is the iris, which regulates the amount of light entering the eye but is not the same as the conjunctiva. Lastly, the tough outer covering of the eyeball refers to the sclera, which protects the inner components of the eye and provides structure, different from the function and location of the conjunctiva.