Differential Diagnosis 
of 
Common Physical Signs in Orbit

 
Enophthalmos
(This is the backward displacement of the globe into the orbit. The most common cases in the examination are orbital floor fracture and small globes of various causes)

Apparent or pseudo-enophthalmos

  • Horner's syndrome (due to narrowing of the palpebral fissure)
  • Muscle resection
    • Increased in the volume of the orbit
  • blow-out fracture (which allows herniation of the orbital content)
  • destruction of the orbit (this may be caused by tumours, infection or chronic inflammation of the sinus)
  • congenital absence of the orbital wall (the classical type is absence of sphenoid wing in neurofibromatosis)
    • Cicatricial changes
    (this causes traction of the globe)
  • metastatic tumours (classically breast carcinoma)
  • post-inflammation (such as following pseudotumour)
  • post-trauma
    • Loss of orbital content
    (the two main causes are loss of orbital fat and globe volume)
  • orbital fat atrophy (this may be involutional (age-related), post-traumatic, post-radiation or severe wasting diseases)
  • loss of globe volume (seen in microphthalmos, post-enucleation socket syndrome and phthisical bulbi)


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    Exophthalmos
    (This is defined as protrusion of the globe due to increased orbital content, by far the commonest cause for axial/non-axial or unilateral/bilateral exophthalmos in the clinical examination is thyroid eye disease. )

    Pseudo-exophthalmos

  • lid retraction (this can give the appearance of proptosis due to showing of the sclera)
  • large globe (seen in high myopia or bulphthalmos)
  • extraocular muscle problems (paralysis of the extraocular muscles decreases the muscle tone and make the globe appears protruded, another cause is recession of the muscles)
  • contralateral enophthalmos
  • shallow orbit (in craniofacial syndromes such as Courzon's syndrome and Apert's syndrome)
    • True exophthalmos
    (In clinical examination this may be divided into axial or non-axial; axial proptosis suggests the presence of a pathology process in the muscle cone whereas non-axial outside the muscle cone. However, for simplicity, the mnemonic VEIN= Vascular causes + Endocrine causes + Infective/Inflammatory causes + Neoplastic causes is used)

    Vascular causes

  • Cavernous haemangioma
  • Varix
  • Carotid cavernous fistula
  • lymphagioma
    • Endocrine
  • Thyroid orbitopathy
    • Infection /  Inflammation
  • orbital cellulitis
  • inflammatory conditions (sarcoidosis, Wegener's granulomatosis)
    • Neoplastic
  • in the muscle cone (glioma and meningioma of the optic nerve)
  • arising from the muscles (lymphoid tumours, metastasis)
  • lacrimal ( pleomorphic adenoma, lymphoma, adenoid cystic adenoma)
  • bony lesions ( metastatic carcinoma, dermoid cyst, cholesteatoma, histiocytic lesions)
  • periorbital (sinus carcinoma or mucocele)
  • others (rhabdomyosarcoma, encephalocele, teratoma, neurofibroma, various vascular tumours)


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