Bulbar conjunctiva

Recommended video: Eyeball [25:37]

Structure of the eyeball seen in a transverse section.

The bulbar conjunctiva, also called the ocular conjunctiva, is a thin, transparent, specialized membrane which lines the sclera (white part) of the anterior surface of the eyeball.

It forms part of the conjunctiva, which has two main sections: the bulbar conjunctiva and the palpebral conjunctiva, which lines the internal aspects of the eyelid. Together, these sections form the conjunctival sac, which opens through the palpebral fissure.

A deep recess called the conjunctival fornix forms at the junction of the bulbar and palperbral conjunctiva both superiorly and inferiorly.

The bulbar conjunctiva is composed of non-keratinized stratified squamous epithelium with scattered mucous-secreting goblet cells and an underlying fibrous layer (substantia propria). It is loosely attached to the visible portion of the sclera but is adherent to the edge of the cornea, between the sclera and the cornea (corneoscleral junction), and does not cover the cornea.

The bulbar conjunctiva is well vascularized, with vessels becoming more prominent when the conjunctiva is irritated or inflamed. It is supplied by the palpebral arcades and anterior ciliary arteries and ultimately drain into the ophthalmic veins. It receives sensory innervation from the ophthalmic and maxillary branches of the trigeminal nerve, along with some autonomic nerve fibers.

The primary functions of the bulbar conjunctiva include the protection of the eyeball from various hazards in the environment including foreign pathogens, as well as the lubrication of the eyeball, allowing for smooth blinking.