enophthalmos

Enophthalmos is the posterior displacement or sinking of the eyeball within the orbit, giving a sunken appearance. It can affect one or both eyes and may be static or progressive, depending on the underlying cause.

Causes and pathophysiology include trauma, particularly blowout fractures of the orbital floor or medial wall, which increase orbital volume and allow the globe to recede. Chronic enophthalmos can follow resolution of edema after injury. Other causes include loss of orbital volume from aging or malnutrition, orbital fat atrophy, inflammatory or fibrotic processes, and prior orbital surgery or implant migration. Congenital shallow orbits can predispose to enophthalmos, and conditions such as Horner syndrome can be associated with mild inward displacement due to edema and fat atrophy of periorbital tissues.

Clinical features and diagnosis rely on a careful ocular examination. Exophthalmometry (for example, Hertel exophthalmometer) measures globe position relative to the orbital rim; a difference of more than about 2 to 3 millimeters between eyes is typically considered abnormal. Imaging, usually CT or MRI, is used to assess orbital contents, fractures, fat atrophy, and soft tissue changes. Clinically important differential diagnoses include pseudoenophthalmos from eyelid retraction or deep-set eyes, and true enophthalmos due to the conditions listed above.

Management depends on the cause. Traumatic enophthalmos may require orbital floor or wall reconstruction with implants or bone grafts to restore orbital volume. Non-traumatic, age-related, or cosmetic deficits may be treated with volume restoration using autologous fat grafts or fillers. In some scenarios, observation is appropriate, and treatment of any underlying systemic or local inflammatory process is indicated. Prognosis varies with etiology and the extent of volume loss; timely diagnosis and appropriate reconstruction improve functional and cosmetic outcomes.