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Editor,—Chronic maxillary atelectasis (CMA),1 also known as silent sinus syndrome (SSS)2 describes the same condition. Typically, the patient presents with acute enophthalmos and hypoglobus in the absence of previous trauma or surgery. Past sinus disease may be present and computed tomograph (CT) scans demonstrate ipsilateral sinus contraction, orbital floor resorption, and thinning with inferior prolapse into the maxillary sinus. We present a patient who noted oscillopsia while jogging 1 year after being diagnosed with SSS.
A 26 year old woman was referred with a 6 month history of painless gradual sinking of the left eye (Fig 1). She had suffered two episodes of mild sinusitis, one at the age of 12 and one at a year before presentation. Visual acuity was 6/6 in each eye and there was no evidence of optic neuropathy. There was 4 mm of left relative enophthalmos, no manifest deviation, and full extraocular movements. The height of the palpebral aperture was 1 mm less on the left. Orbital CT scans showed a unilaterally opaque maxillary antrum and ethmoid sinus, a collapsed infundibulum, an imploding medial wall, and a concave demineralised orbital floor (Fig 2). Eighteen months after becoming symptomatic, the patient spontaneously remarked that she had vertical oscillopsia while jogging.
Oscillopsia is an illusion that the world is in motion; we believe that this is the first report in a patient with SSS. It occurs most frequently with disorders of the vestibular system, cerebellum, or brainstem. Our patient had no associated neurological signs or symptoms, and a normal head CT scan. A mechanical cause of oscillopsia caused by an instability of fixation is a rare but well documented finding.3
In our patient we postulate that the oscillopsia during jogging arises from inadequate globe support caused by demineralisation and downward displacement of the orbital floor and Lockwood's ligament, while the levator palpebrae superioris and Whitnall's ligament remain in their normal position. Patients with SSS may also develop vertical diplopia,4 lid retraction,5lagophthalmos,6 or blurred vision.7
Spontaneous enophthalmos unrelated to trauma, surgery, local malignancy, or systemic disease is uncommon. The presence of diplopia may suggest an underlying neuro-ophthalmic disorder; however, hypoglobus and enophthalmos point to the orbital/maxillary area as the primary site of pathology.