Eye proptosis also referred to as Exopthalmos, is a condition occurring due to forward displacement of the eye. This entity may be also called as eye luxation and eye dislocation. Exopthalmos is a condition where there is bulging of the eye out of the orbit (the bony socket of the eye) anteriorly. Exopthalmos may be one-sided (as seen in orbital tumor) or bilateral (as often seen in Grave’s disease / Thyroid Eye Disease).
If not treated, Exopthalmos may lead to the eyelids remaining open during sleep, causing corneal dryness and damage (due to dry eyes). Another common complication is the redness of the conjunctiva above the cornea (red eyes), as the conjunctiva becomes inflamed, because of increased friction when blinking the eye. The forward displacement of the eye may also lead to compression of the optic nerve or ophthalmic artery, resulting in blindness (loss of vision / sight).
Etiology / Causes of Proptosis:
- Graves’ ophthalmopathy, due to Graves’ disease (Thyroid Eye Disease), usually causes bilateral proptosis.
- Orbital cellulitis – Infection of the orbit. Often presents with unilateral proptosis, severe redness, and moderate to severe pain, sinusitis and an elevated white blood cell count.
- Dacryoadenitis – Inflammation of the lacrimal glands (tear glands)
- Mucormycosis – A kind of Orbital Fungal infection
- Orbital pseudotumor – A non-specific orbital soft tissue inflammation (swelling), that involves any area of the orbit. It presents with acute, usually unilateral proptosis with severe pain.
- High altitude cerebral edema
- Wegener’s granulomatosis – A rare type of vasculitis (inflammation of blood vessels) affecting small and medium-sized vessels in the orbit & many other organs of the body.
Neoplastic (Tumors / Cancers):
- Leukemias – Blood Cancer.
- Meningioma (of sphenoid wing) – varied set of tumors arising from the meninges (coverings of the brain)
- Nasopharyngeal angiofibroma – a benign vascular tumor, which is locally aggressive & found to grow in the back of the nasal cavity. Patients present with unilateral nasal obstruction and continuous bleeding.
- Lacrimal tumors (Tumors of the lacrimal gland) – Like pleomorphic adenomas.
- Cavernous Hemagioma – A vascular tumor.
Orbital Vascular Disease:
- Orbital varix – a thin walled arterio-venous tumor (Blood vessel tumor), enlarged abnormally, that is in direct communication with the normal vessels of the orbit. It’s like a varicose vein behind the eye.
- Orbital arterio-venous malformation (carotico-cavernous sinus fistula)
- Dermoid cyst
- Orbital fractures: apex, floor, medial wall, zygomatic
- Retrobulbar hemorrhage: trauma to the orbit leading to bleeding behind the eye. The hemorrhage has nowhere to escape (given the closed nature of the orbit) & the increased pressure pushes the eye out of the socket, leading to proptosis. This can also cause blindness, if not treated promptly.
- Cushing’s syndrome (due to fat in the orbital cavity)
Pseudoproptosis (pseudoexopthalmos): Conditions causing a false illusion of proptosis or bulging eye(s).
- Buphthalmos – enlargement of the eyeball, most likely seen in infants and young children, due to congenital glaucoma.
- Contralateral enophthalmos – As the other eye retrudes into the orbit, the normal eye gives the illusion of being bigger or bulging.
Posterior displacement of the other eyeball within the orbit, because of changes in the volume of the orbit (bone) relative to its contents (orbital fat and eyeball) or due to loss of functioning of orbitalis muscle.
- Ipsilateral lid retraction – The eyelid retraction (upward movement) can give the illusion of proptosis or bulging eye.
- Axial myopia – nearsightedness/short-sightedness. The larger eyeball due to a negative refractive power, can lead to the illusion of proptosis.
- Contralateral blepharoptosis – abnormal drooping of the eyelids. Drooping of the opposite eyelid (ptosis) can make the normal eye appear bulging.