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 eyes and their relative position to the skull is below. In panel A, the eyes are at roughly equivalent positions with the equator of the eye at or behind the lateral orbital rim. In panel B, the right eye is posteriorly displaced in a relatively enophthalmic position.
Primary enophthalmos indicates a congenital or developmental 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 volumetric relationship between the rigid bone cavity, the orbit, and its contents (predominantly the orbital fat, the extraocular muscles, and the eye). Expansion of the orbital cavity without change in the volume of orbital contents (ie, a blow-out fracture) leads to enophthalmos.[1] An example of a blow-out fracture is shown in the image below. The arrow points to the downward displacement of the orbital floor bone into the blood-filled maxillary sinus.
Spontaneous enlargement of the orbit may also occur in silent sinus syndrome, as depicted in the figure below, where a negative pressure develops within the maxillary sinus, thinning the orbital floor and drawing it downward. The maxillary sinus is filled with mucoid material, not blood, in silent sinus syndrome.
Alternatively, scarring contracture of the orbital fat and extraocular muscles may decrease soft tissue volume, making the orbital cavity less full and causing enophthalmos. Several disorders may cause this, including metastatic sclerosing or scirrhous breast carcinoma.
United States
Enophthalmos is common.
International
Same as in the United States.
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.
This condition occurs at all ages, but different ages have different common etiologies.
The prognosis of enophthalmos is directly related to both the underlying cause and the degree of deformity.
Most causes of enophthalmos are treatable, and surgical correction is most frequently excellent following outpatient surgery.
Perhaps the single most important advice to give a patient until the workup of suspected new-onset enophthalmos has been completed is not to blow their nose and to sneeze with their mouth open.
One of the most common causes of enophthalmos is orbital fracture. Barometric changes in the nasopharynx (wind velocity may exceed 200 mph during a sneeze) can force air into the orbit. The loose orbital fat may then fall back into place covering the bone defect, acting as a ball valve, trapping the air, and creating an acute orbital compartment syndrome with blinding potential.
Other causes of bone loss between the orbit and the sinuses (most notably varix and silent sinus syndrome) also may be affected by dramatic barometric pressure changes.
Enophthalmos may be sudden and static, non-changing (as may occur with trauma) or progressive. Sudden appreciation of enophthalmos does not necessarily imply sudden development. Depending on the cause, enophthalmos may progress over any time frame, ranging from minutes to years. Most causes of enophthalmos are progressive, including trauma and congenital deformities, because inflammation and swelling immediately after trauma may prevent achievement of the total final degree of enophthalmos, and congenital enophthalmos may progress as certain parts of the face continue to develop while others do not.
Mild degrees of bilateral enophthalmos may be difficult to determine without radiographic studies or old photographs for comparison, but unilateral enophthalmos is often obvious when comparing one eye with the other. Specific changes include the following:
Causes of secondary enophthalmos include the following:
The degree of enophthalmos is often appreciated and measured using an exophthalmometer, of which several varieties are available. However, exophthalmometer measurements are highly position– and applied pressure–dependent, and the reliability of measurements, especially as performed by different examiners, may be low.
"Worms' eye" photographs, such as that shown in the image below, can be very helpful in documenting and monitoring enophthalmos. The photographs are taken at a standardized angle of head tilt, for example placing the tragus of the ear and the projection of the chin in a line parallel to the floor. An assessment of the anterior corneal projection, marked "CP" below, may be compared to the frontal process projection "FP" and the maxillary process projection "MP." In this photograph, the left eye is enophthalmic. If the lateral orbital rim is posteriorly displaced or the maxilla is hypoplastic or in-fractured, the more common exophthalmometers will provide inaccurate measurements.
Long-standing enophthalmos, especially associated with very extensive orbital trauma, may be associated with severe orbital scarring, and correction can be very difficult or impossible.
Complications of enophthalmos are mostly aesthetic, but certain problems may be associated with a posterior position of the eye, including the following:
Other complications may be associated with the development of enophthalmos, but not caused by the enophthalmos. Examples might include other facial trauma or systemic malignancy.
Congenital enophthalmos
Soft-tissue intraorbital deficiency, such as microphthalmos or anophthalmos
Bone growth problems
Orbital cavity expansion
Orbital bone out-fracture
Surgical expansion, ie, orbital decompression
Silent sinus syndrome
Orbital varix
Granulomatous, bone necrosing disorders
Pseudoenophthalmos
Ipsilateral upper eyelid ptosis and/or lower eyelid reverse ptosis
Superior sulcus volume loss or elevated eyelid crease
Horner syndrome
Pseudoenophthalmos due to contralateral exophthalmos
Tumor
Orbital bone in-fracture, such as ZMC fractures
Thyroid ophthalmopathy
Pseudoenophthlamos due to contralateral pseudoexophthalmos
High myopia
Buphthalmos
Megaloglobus
Eyelid retraction
Lagophthalmos (ie, Bell palsy)
Volumetric loss of orbital soft tissue contents
Orbital fat atrophy
Orbital fat sclerosis and contraction
Following orbital tumor resection
Small or shrinking eye
Neuroimaging is the most essential laboratory study in patients with enophthalmos. The remainder of laboratory studies are guided by suspected etiology.
The following imaging studies might be considered:
Other tests are determined by the specific suspected disease process. For example, in the case of suspected contralateral orbital tumor, systemic evaluation for a primary malignancy and metastatic disease should be performed.
Open biopsy may be indicated. Needle biopsy is rarely helpful in the diagnosis of enophthalmos.
The wide range of causes for enophthalmos provides a wide range of histopathologic findings. One of the most curious findings may be silent sinus syndrome, in which spontaneous enophthalmos and hypoglobus occur over days to years without any associated trauma and the histopathology shows only mild, chronic mucosal inflammation and bone reparative changes.[4, 5, 6]
The degree of enophthalmos is usually measured in millimeters relative to the contralateral eye and documented as millimeters of relative enophthalmos.
Medical treatments in patients with enophthalmos are directed at specific diseases and may include chemotherapy or ionizing radiation for metastatic disease or immunosuppressive treatments for inflammatory disorders. Once the disease process is stabilized, nonsurgical management may include camouflage glasses (hyperopic [magnifying] correction over myopic contact lens).
Once medical or surgical treatment of the underlying process is achieved, correction of enophthalmos begins with approximating normal orbital bone positions before addressing soft tissue volume loss.[7, 8]
Orbital fracture repair includes the following:[9]
Maintain the convexity of the posterior, medial orbital floor.[10]
Stabilize floor implants posteriorly on intact floor ledge.
Release any major adhesions or scar bands to allow mobilization of soft tissues. In late posttraumatic cases, sharp rather than blunt dissection is often required.[11]
If using bone grafts rather than synthetic materials, allow for 15-30% resorption.
Overcorrect to obtain 1-2 mm of exophthalmos intraoperatively.
Perform forced duction testing of the globe prior to closure.
In replacing lost orbital soft tissue volume, perform the following:
A forward traction test on the globe to determine the amount of correction possible
Augment from the orbital walls inward with bone or synthetic materials. For pure enophthalmos correction without hypoglobus, inferolateral and retrobulbar mass effect is desirable.
Consultation with oculoplastic surgery or neuro-ophthalmology may be useful in defining the cause of enophthalmos.
Activity restrictions depend on the etiology.
Follow-up depends on the etiology of enophthalmos.
Management and inpatient care directly depend on the etiology of the enophthalmos and related comorbidities.
Medication depends on the etiology.