Exophthalmos: definition, symptoms, causes and treatment

By Cristiano Antonino On Apr 29, 2023

Exophthalmos refers to a protrusion of the eyeball, which exits the orbits beyond the eyelid rima. It is also known by the term proptosis or the more common expression ‘eyes out’, although exophthalmos is usually associated with endocrine-related alterations

The eye is positioned in the orbit, which is formed by bony walls that cannot, in normal situations, deform.

This is why it is usually an increase in the volume of the orbital contents that shifts the position of the eye.

The latter is in fact generated by a number of variables, such as eye size, orbit volume, extra-orbital muscles and retro-orbital fat.

If one of these variables is altered, the eye protrudes forward, resulting in exophthalmos.

Exophthalmos can be distinguished into two types:

direct, when the eye is pushed forward
indirect, when the eyeball is also moved laterally

Symptoms of exophthalmos

Usually one eye out is visible, although in the early stages, i.e. in the presence of mild exophthalmos, the disorder may not give any symptoms.

When the protusion is significant, however, the consequence is a misalignment that gives rise to diplopia.

If the eye is then so far forward that it cannot be completely covered by the eyelid, the patient may present with exposure keratitis.

A condition that could cause severe damage to the cornea and conjunctiva, up to and including ulcerations that impair vision and cause severe pain.

Ultimately, symptoms that should prompt an urgent visit to an ophthalmologist include:

reddening of the eyes
pain
diplopia
headache
visual deficits
fever
pulsating proptosis

Exophthalmos: main causes

The causes of exophthalmos can be diverse and not all related to the visual apparatus.

In some cases, as we said, the origin lies in endocrine system issues.

In any case, the overeye is always caused by an increase in volume of the orbital contents, but this can have different origins.

Among the most common causes that can give rise to exophthalmos are:

hyperthyroidism (in particular Graves’ disease – Basedow)
tumours, with the presence of a mass in the orbital cavity
inflammation, when physical, infectious or traumatic causes cause oedema that ‘pushes’ on the eye
vascular changes, such as carotid-carvernous fistula, which causes pulsatility

Other causes of proptosis may be

progeria, a rare genetic disease that causes premature and progressive ageing of the body, already present in childhood
infectious cellulitis, an inflammation of the skin and subcutaneous tissue caused by bacterial infection, a primary cause of exophthalmos in children
glaucoma, an eye disease caused by increased eye pressure
dacryocystitis, an inflammation of the lacrimal sac often caused by an infection with streptococci or staphylococci
leukaemia
meningioma, a type of brain tumour
neuroblastoma, a malignant tumour that particularly affects children
spherocytosis, a hereditary form of chronic haemolytic anaemia
vitiligo, a skin disease in which the body does not produce or produces low amounts of melanin
Cushing’s disease, a disease caused by excessive pituitary production of adrenocorticotropic hormone
severe obesity

How exophthalmos is diagnosed

The first thing to do when you have one or more symptoms related to exophthalmos is to book an eye examination to check with the specialist whether or not you have proptosis.

The first step is a careful anamnesis, followed by a general eye examination in which the direction of proptosis, its unilaterality or bilaterality, any other defects such as strabismus, ptosis or abnormalities of the eyelid or conjunctiva are assessed.

The doctor then performs exophthalmometry, a test that measures the distance between the lateral angle of the orbital bone and the cornea using a special instrument called a Hertel exophthalmometer.

The ophthalmologist will also palpate the orbital rim looking for any masses, and will complete with a visual acuity check, an eye motility assessment and a fundus test.

Ocular ultrasound can also prove to be a valuable aid in assessing the state of the extraocular muscles and orbital soft tissues.

In addition, the specialist can use computed tomography of the eye, a diagnostic imaging test that allows a more precise analysis of the internal structures of the eye and the tissues present in the orbital cavity.

Magnetic resonance imaging can also be useful in understanding not only whether one has proptosis, but also what causes it.

These tests are particularly good for ruling out tumours, trauma, vascular pathologies and other disorders that can cause an increase in the orbital cavity content.

If they do not show anything, the state of the thyroid gland will be assessed to look for any imbalances.

Care and treatment of exophthalmos

The treatment of protruding eyes depends on the origin of the proptosis itself.

It is therefore necessary to identify the origin of the problem: in some cases, such as in the presence of tumours or infections, it is sufficient to resolve the cause to see the exophthalmos recede.

Other times, however, especially if the proptosis is linked to hereditary or endocrine disorders, it cannot always be completely resolved but only treated.

When the eye is completely uncovered, in order to avoid exposure keratitis and damage to the cornea or conjunctiva, lubrication with artificial tears is carried out.

When exposure keratitis is already present, antibiotic treatment is usually carried out to avoid infection.

In some cases, surgery may be necessary to at least partially remedy the exposure of the cornea by covering it.

Usually an orbital decompression is performed, increasing the volume of the orbit.

The latter is particularly useful when one is faced with thyroid pathology, but also when exophthalmos causes damage to the optic nerve that could lead to irreversible loss of vision.

Exophthalmos, or proptosis, is also called eye out precisely because it consists of the eyeballs protruding forward.

It can be caused by diseases, trauma, tumours, infections or endocrine disorders, and cannot always be completely resolved.

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