An important structure on the surface of the eye is one you can’t easily see — it’s called the conjunctiva.

Conjunctiva definition

The conjunctiva is the clear, thin membrane that covers part of the front surface of the eye and the inner surface of the eyelids. It has two segments:

Bulbar conjunctiva. This portion of the conjunctiva covers the anterior part of the sclera (the “white” of the eye). The bulbar conjunctiva stops at the junction between the sclera and cornea; it does not cover the cornea.

Palpebral conjunctiva. This portion covers the inner surface of both the upper and lower eyelids. (Another term for the palpebral conjunctiva is tarsal conjunctiva.)

The bulbar and palpebral conjunctiva are continuous (see illustration). This feature makes it impossible for a contact lens (or anything else) to get lost behind your eye.