Exophthalmos, also known as ocular proptosis, is a striking symptom: it manifests as an abnormal protrusion of one or both eyeballs from the eye socket. This gives the impression that the eyes are “popping out” of their sockets.
Exophthalmos: a symptom, not a disease
First and foremost, it is important to understand that exophthalmos is not a disease, but a symptom. It indicates that something abnormal is happening in the eye socket, often related to inflammation, a tumor, or a hormonal imbalance.
The most common cause is autoimmune hyperthyroidism, more specifically Graves' disease.
The main causes of exophthalmos
1. Graves' disease: This is the most common cause of bilateral exophthalmos. It is an autoimmune disease in which the immune system attacks the thyroid gland, causing hyperthyroidism. This attack can also target the tissues around the eyes, causing inflammation, swelling, and fibrosis. As a result, the eyeballs are pushed forward. This is known as dysthyroid ophthalmopathy.
2. Orbital tumors: A benign or malignant tumor in the orbit can exert pressure that pushes the eye outward. This can be:
- A meningioma,
- A lymphoma,
- A hemangioma,
- A metastasis.
Depending on the type and location of the tumor, exophthalmos can be unilateral (affecting only one eye) or bilateral.
3. Orbital infections and inflammation: Certain serious infections, such as orbital cellulitis, can cause sudden, painful exophthalmos accompanied by fever. This is a medical emergency, often of bacterial origin (following sinusitis, for example).
4. Trauma: A violent blow to the eye or face can cause a retro-orbital hematoma, which puts pressure on the eyeball and pushes it forward. This is also an emergency.
5. Vascular malformations: Abnormalities in the blood vessels around the eye, such as a carotid-cavernous fistula, can increase pressure in the orbit and cause pulsatile exophthalmos (the eye “beats” with the heartbeat).
What are the associated signs?
Depending on the cause, exophthalmos may be accompanied by:
- Dry eyes or watering
- Pain
- Double vision (diplopia)
- Redness or swelling of the eyelids
- Decreased vision in severe cases
When to seek medical attention
Any sudden, painful exophthalmos or exophthalmos accompanied by vision problems requires an urgent consultation with an optometrist. Prompt treatment can often prevent complications such as vision loss.
Exophthalmos is a warning sign: it draws attention to an underlying medical problem, whether hormonal, tumorous, infectious, or vascular. The most common cause is Graves' disease, but other possible causes should never be overlooked. A medical evaluation, often accompanied by imaging (CT scan, MRI), is essential to make an accurate diagnosis and begin appropriate treatment.
