Which membrane lines the eyelids and covers the exposed surface of the eye?

The conjunctiva is the membrane that lines the eyelids and covers the exposed surface of the eye. It plays a crucial role in protecting and lubricating the eye by spreading tears across the surface and helping to keep the eye moist. This thin, transparent tissue helps minimize friction between the eyelids and the eyeball during blinking, and it also provides a barrier against pathogens and foreign particles.

In contrast, other structures like the cornea, sclera, and retina have different functions: the cornea is the clear front part of the eye that helps focus light, the sclera is the white outer coat that provides structure and protection, and the retina is the innermost layer that contains the photoreceptors responsible for converting light into neural signals for vision. Understanding the specific roles of these components highlights the unique and vital function of the conjunctiva in maintaining eye health.