The episclera is the outermost layer of the sclera

Sclera

The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...

. It is composed of loose, fibrous, elastic tissue and attaches to Tenon's capsule.

A vascular plexus is found between the conjunctiva and the sclera consisting of two layers of vessels, the superficial episcleral vessels and the deep episcleral vessels.

Clinical significance

In episcleritis, the episclera and Tenon's capsule are infiltrated with inflammatory cells
.