Proptosis: definition, causes, types, measuring, management

Definition: Protrusion of the globe with respect to the orbit. Proptosis and exophthalmos are often used interchangeably. Exophthalmos is often used to refer to endocrine-related causes.

What is the Etiology (causes) of Proptosis?

1. Thyroid orbitopathy (most common cause of uni/bilateral proptosis in adults).
2. Nose & paranasal sinuses (infections or neoplasm)
  • Frontal: mucocele, osteoma: downwards & lateral.
  • Ethmoid: mucocele, osteoma, malignancy: lateral.
  • Maxillary: malignancy: upwards.

3. Lacrimal gland causes: Downwards & medial.
4. Orbital causes: e.g. hematoma, abscess, and tumors leading to forward proptosis.
5. Nasopharyngeal causes: fibroma, carcinoma.

6. Cavernous sinus thrombosis. 
7. Orbital inflammatory syndrome (orbital pseudotumor). 
8. Pseudoproptosis (false impression of proptosis: contralateral enophthalmos).

Classification of proptosis:

  1. Acute proptosis: orbital emphysema & hemorrhage.
  2. Intermittent proptosis: periodic orbital edema.
  3. Pulsating proptosis: caroticocavernous fistula.

How to measure proptosis?

Hertel mirror exophthalmometers are used to measure the degree of protrusion of the eyeball. The distance between the lateral orbital rim and corneal apex is used as an index for measuring proptosis. Under normal conditions this distance is roughly 18 mm.

How to manage proptosis?

  1. Specific management is directed towards treating the cause for proptosis.
  2. Medical Treatment: artificial tears, Steroids, Diuretics.
  3. Local measures: sun glasses, sleeping in supine position with head elevated.
  4. Orbital decompression is indicated if:
  • Visual disturbance.
  • Failure of steroids to improve vision.
  • To prevent exposure keratitis.
  • Diplopia.
  • Cosmetic.
Proptosis: definition, causes, types, measuring, management
Dr.Tamer Mobarak


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