Enophthalmos is the posterior displacement of the eyeball within the orbit due to changes in the volume of the orbit (bone) relative to its contents (the eyeball and orbital fat), or loss of function of the orbitalis muscle. It may be a congenital anomaly, or be acquired as a result of trauma (such as in a blowout fracture of the orbit), Horner`s....
Sunken eyeball. ... (12 Dec 1998) ... 
(en″of-thal´mos) a backward displacement of the eyeball into the orbit.
The recession of the eyeball into the cavity of the orbit.
Type: Term Pronunciation: en′of-thal′mos Definitions: 1. Recession of the eyeball within the orbit. Synonyms: enophthalmia
Enophthalmos: Sunken eyeball.
Recession of the eye deep within the orbit
Retraction of globe into the orbit resulting in a sunken eye.