[TA] a condensation of connective tissue on the outer aspect of the sclera from which it is separated by a narrow cleftlike episcleral space; the sheath is attached to the sclera near the sclerocorneal junction and blends with the fascia of the extraocular muscles. SYN: vagina bulbi [TA], capsula bulbi, eye capsule, fascia bulbi, sheath of eyeball, Tenon capsule, vagina oculi.