Exophthalmos, also known as proptosis, is the medical term for bulging or protruding eyes. Exophthalmos happens when one or both eyes protrude from the eye socket—often due to swelling of the muscles and fatty tissue behind and around the eye. This causes more of the cornea to be exposed to air, making it more difficult to keep eyes moist and lubricated.
Exophthalmos can affect one or both eyes and is most often caused by thyroid eye disease (TED) or Graves opthalmopathy disease—an autoimmune condition where the immune system mistakenly attacks healthy tissue.
It appears that the same antibody that can cause thyroid dysfunction may also have an "attraction" to tissues surrounding the eyes, causing the onset of Graves ophthalmopathy. When related to Graves disease, you may hear the term exophthalmos used instead of bulging eyes.
Oftentimes prominent eyes are mistaken for bulging eyes. Prominent eyes are generally hereditary, and in most cases harmless. However, bulging eyes are different, as they may be linked to a more serious condition in need of urgent attention. In extreme cases, bulging eyes can create a large amount of pressure on the optic nerve, potentially leading to vision loss if not promptly treated.
It is always recommended that you consult with your eye doctor and maintain regular, comprehensive eye exams to maintain healthy vision.
Though less common, other potential causes of exophthalmos include:
- Eye injury
- Bleeding behind the eyes
- Abnormally shaped blood vessels behind the eyes
- Infection of the tissue in the eye socket
- Cancerous tumors
Symptoms of Bulging Eyes
Bulging eyes are usually a symptom of another condition. Symptoms of bulging eyes may include the following:
- Appearance of protruding eyes
- Excessive dryness in eyes
- Visible whiteness between the top of the iris (the colored part of the eye) and the eyelid
Depending on what’s causing bulging eyes, there may be other associated symptoms. If, for example, thyroid eye disease is the underlying cause for exophthalmos, you may experience the following symptoms:
- Inflamed, red and painful eyes
- Dry and “gritty” sensation
- Tearfulness
- Sensitivity to light (photophobia)
- Double vision
See your eye doctor if you notice that one or both eyes are bulging. It’s important to identify the cause, since treatment is most effective when started as soon as possible.
What Happens During an Eye Exam for Bulging Eyes?
If you are referred to an eye specialist (such as an ophthalmologist), they may:
- Arrange for blood tests
- Use an exophthalmometer, which is an instrument that measures how far the eyeball protrudes
- Assess how well you’re able to move your eyes
- Arrange for a CT or MRI scan to check for:
- Bleeding
- Abscess or infection of the eye area
- Broken eye socket bone
- TED/Graves ophthalmopathy disease
- Foreign object in the eye socket
- Tumor
Early detection of the underlying cause of exophthalmos is vital for successful treatment.
Treatment for Bulging Eyes
The underlying cause of bulging eyes will determine the overall course of treatment. However, in all cases, bulging eyes will be exposed to more air, making it difficult to keep them lubricated.
- Artificial tears and eye drops can be used to combat excessive dryness and irritation by adding moisture and lubrication
- The use of special lenses can help correct double vision
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