Proptosis

Proptosis, also called exophthalmos, is the forward displacement of the eyeball from the orbit. It may be unilateral or bilateral and is often noticed by a clinician or the patient, who may also report eyelid retraction, tearing, or double vision. Measurement of the protrusion can be done with a Hertel exophthalmometer, and it is important to distinguish true proptosis from pseudoproptosis caused by eyelid or facial swelling.

Causes are diverse and commonly categorized as inflammatory/infectious, vascular, neoplastic, traumatic, or congenital. The most frequent cause in adults is Graves’ disease (thyroid-associated orbitopathy). Other etiologies include orbital inflammatory disease, orbital cellulitis, orbital tumors, carotid-cavernous fistulas, hemorrhage within the orbit, and post-traumatic or postoperative changes.

Pathophysiology generally involves expansion of contents within the orbit—such as fat, extraocular muscles, inflammatory tissue, blood, or tumor mass—which produces forward displacement of the globe. In severe cases, proptosis can compress the optic nerve or impair ocular blood flow, risking vision.

Clinical features vary with cause but commonly include eye bulging, diplopia, lid retraction, conjunctival redness or swelling, tearing, and sometimes pain. Visual changes warrant urgent assessment.

Evaluation combines history, visual acuity and field testing, ocular motility assessment, and measurement of proptosis. Imaging with CT or MRI helps define orbital masses, inflammation, or vascular abnormalities. Thyroid function tests are often obtained when thyroid eye disease is suspected.

Management is cause-specific. Emergent treatment is required for sight-threatening conditions such as orbital cellulitis or compressive optic neuropathy. Interventions may include antibiotics, corticosteroids or immunosuppressants, radiotherapy, orbital decompression or tumor-directed surgery, and supportive measures like lubrication to protect the cornea. Prognosis depends on the underlying cause and timeliness of treatment.