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Man presents with gradual, painless enophthalmos
A CT scan showed increased orbital volume in the right eye with no obvious fracture and a smoothly rounded, deepened orbital floor.
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A 39-year-old man presented to his ophthalmologist with a complaint of his right eye looking “different” from his left eye for the past 6 months. He denied any pain, foreign body sensation, double vision or other ocular complaints. He also denied any history of trauma or recent facial surgery; he had a history of a broken nose as a teenager and nasal surgery to correct it at that time.
The patient’s ocular history was significant for myopic LASIK correction in both eyes 2 years before presentation. His family history was noncontributory. He was a nonsmoker and drank alcohol socially.
Examination
On examination, uncorrected visual acuity was 20/20 in both eyes. The patient had the appearance of right pseudoptosis with a normal marginal reflex distance bilaterally and a deeper superior sulcus in the right eye. He had 2 mm of enophthalmos in the right eye. (Figure 1). Anterior slit lamp exam was remarkable for intact LASIK flaps in both eyes. IOP was normal, and pupils were equal and reactive without a relative afferent pupillary defect.
A CT scan of the orbits was performed and showed increased orbital volume in the right eye with no obvious fracture and a smoothly rounded, deepened orbital floor (Figure 2). There was also apparent maxillary sinus volume loss and inward retraction of the sinus walls.
Figure 1. Full frontal face shows right hypoglobus and pseudoptosis, and looking down demonstrates right enophthalmos.
Images: Renz J, Kapadia M
Figure 2. CT of the orbits shows increased right orbital volume and decreased maxillary sinus volume with retracted walls.
What is your diagnosis?
Painless enophthalmos
The differential diagnoses for painless enophthalmos and hypoglobus include processes that increase orbital space and those that decrease or contract orbital content.
Missed traumatic fracture is the most common cause of increased orbital space and enophthalmos. Typically, there is evidence of previous fracture, irregular contour on CT, and no inward displacement of the maxillary sinus. The time course is nonprogressive. Facial asymmetry, eg, agenesis of the sphenoid wing or maxillary hypoplasia, may result in a larger orbit but is present at birth. Age-related fat atrophy can reduce orbital content in older patients. Lipodystrophy secondary to HIV, linear scleroderma and hemifacial atrophy are relatively rare causes of orbital wasting and enophthalmos. Fibrosis and scarring from metastatic breast cancer can also manifest as enophthalmos. Enophthalmos can also represent contralateral exophthalmos, or pseudoenophthalmos.
This patient’s CT scan showed no evidence of masses, scarring or previous trauma, and he had findings of an enlarged right orbit with a smoothly convex floor with inwardly retracted maxillary sinus, which is pathognomonic for silent sinus syndrome.
Discussion
Also known as imploding antrum syndrome or chronic maxillary sinus atelectasis, silent sinus syndrome is thought to result from obstruction of the maxillary ostium by the uncinate process, leading to negative pressure formation. Stagnant mucus then causes inflammation and eventually osteolysis. Propensity toward developing this disease may be influenced by a history of nasal sinus surgery or trauma. It is nearly always painless and without sinus complaints, thus meriting the designation “silent.” Appearance on imaging is classically described as maxillary sinus volume loss and inward retraction of sinus walls, with increased orbital volume and retraction and thinning of the orbital floor. This can result in 1 mm to 5 mm of enophthalmos and 0 mm to 6 mm of hypoglobus. There are often abnormalities of the osteomeatal complex seen with the nasal septum deviated toward the involved side, and the maxillary sinus may be partially or completely opacified. There is also often accompanying periorbital signs such as lid retraction, lid lag or deepening of the superior sulcus. Less commonly seen are lagophthalmos, ptosis, diplopia and a unique clicking sound when blinking, caused by air trapped in the conjunctival recess.
Reported cases are rare. It affects men and women equally in the third to fifth decade of life, many with a history of sinus surgery or abnormal nasal anatomy. Soparkar et al noted varied changes in the appearance of the maxillary walls and sinuses. Onset is spontaneous and sudden and can be rapidly progressive in the short term, which reportedly ranges from 3 to 8 months to 3 years. Once progression ends, the deformity is usually stable. The recommended treatment is endoscopic maxillary antrostomy with uncinectomy to relieve the obstruction of the maxillary ostium. If the patient is symptomatic, an orbital floor implant can be placed at the same time, or it can be staged after stability is assured.
The patient was not symptomatic and had been stable for several months. Observation was deemed the most appropriate intervention.