The “conjunctiva” is a thin, transparent membrane that covers the front of the eyeball from behind the eyelid and plays an important role in protecting the eye.
The conjunctiva is divided into the “bulbar conjunctiva,” which covers the surface of the white of the eye, and the “palpebral conjunctiva,” which is the part behind the eyelid.

The main functions of the conjunctiva are as follows:
– Barrier function to protect the eye from foreign substances such as bacteria, viruses, dust, and pollen
– Helps secrete tears, moistens the eyes, and prevents dryness
– The conjunctiva is rich in blood vessels, supplying nutrients and oxygen to the surface of the eye

When bacteria or viruses invade the conjunctiva, inflammation occurs, causing the eye to become bloodshot.

Typical diseases that occur in the conjunctiva include conjunctivitis and pterygium.
(For more information on each disease, please see the “Eye Diseases” page.)

When the white parts of your eyes turn yellow or red, it’s a sign of some kind of condition or illness.

If you have any symptoms that concern you, please check with an ophthalmologist.