Background
Enophthalmos is posterior displacement of the eye. The anterior projection of the eye is most commonly measured relative to the outer edge of the orbit, the orbital rim, but may also be assessed relative to the frontal and maxillary prominences, or the contralateral eye. An image of the eye and orbit anatomy is presented below.
Pathophysiology
Primary enophthalmos indicates a congenital etiology. Some degree of facial asymmetry is common, but congenital relative enophthalmos or ocular retrusion may occur with in utero maldevelopment (eg, plagiocephaly, microphthalmos).
Secondary enophthalmos is due to an acquired change in the volumetric relationship between the rigid bone cavity, the orbit, and its contents (predominantly the orbital fat and the eye). Expansion of the orbital cavity without change in the volume of the orbital contents (ie, a blow-out fracture) leads to enophthalmos. [1] An example of a blow-out fracture is shown in the image below.
Alternatively, scarring contracture of the orbital fat and extraocular muscles may decrease soft tissue volume, making the orbital cavity less full and causing enophthalmos.
Epidemiology
Frequency
United States
Enophthalmos is common.
International
Same as in the United States.
Mortality/Morbidity
Enophthalmos greater than 2 mm relative to the contralateral eye creates an observable cosmetic deformity. Depending on the etiology, other significant morbidity may be associated.
Age
This condition occurs in all ages.
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Eye and orbit.
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Conventional frontal tomograph of a blow-out fracture.
