What Is a Conjunctival Injection?

A conjunctival infection, also referred to as conjunctivitis, pink eye, red eye and madras eye, is an infection of the conjunctiva. The conjunctiva is the clear membrane that covers the inside of the eyelid and the sclera.

When the conjunctiva is infected, the inflammation causes the blood vessels to become highly visible, resulting in a pink or red color. The symptoms include tearing, swollen eyelids, itchiness, discharge, pain, sensitivity or a feeling of irritation in the eye.

In most cases, the causes of a conjunctival infection include allergens, bacteria, viruses, fungi or environmental factors, such as air pollution or chemicals, in liquid form or vapors, that irritate the eye. Environmental irritants include dust, smoke, perfume and cosmetics. In infants, a blocked tear duct may be the cause.

Conjunctivitis is most frequently caused by adenoviruses, such as that caused by the herpes simplex virus. There are enteroviruses that cause acute hemorrhagic conjunctival infections, which have become epidemics in the past.

Conjunctival infections that are caused by allergens or environmental irritants are not initially contagious, but can leave the conjunctiva open to a bacterial or viral infection, which can easily be transmitted to other people. Conjunctival infections can be spread from person to person, from solid objects to a person or from water sources to a person.