Bulging eyes

Bulging eyes are also known by the medical terms exophthalmos and proptosis. Some people are born with protruding eyes as a natural feature of their appearance, but developing bulging eyes can be the sign of an underlying medical condition. One or both eyes can be affected, and the causes vary. The most common reason for bulging eyes is thyroid eye disease.

Other symptoms of bulging eyes can include redness and dry eyes, discomfort, and vision problems, including double vision. See your GP or optician if you notice changes to your eyes or vision. If changes develop suddenly, get urgent medical help by calling 111.

Once the underlying cause of bulging eyes has been diagnosed, a treatment plan can be made to help prevent permanent vision loss and improve the appearance of your eyes. You may see an ophthalmologist and other specialists depending on your diagnosis.

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What is exophthalmos (proptosis)?

Exophthalmos and proptosis are both medical names for bulging eyes. Bulging eyes differ from naturally protruding eyes, and as well as appearing to bulge out can cause symptoms including redness, dryness, and vision problems. Bulging eyes happen due to an underlying eye problem or health condition, most often thyroid eye disease. Other less common causes include tumours, infection and eye injury.

Bulging eyes symptoms

The most obvious eye sign is one or both eyeballs protruding more than normal, sometimes giving the eyes a startled appearance. The white of the eye may be visible without lifting the eyelid. Bulging eyes can develop gradually or suddenly, depending on the cause. Symptoms can vary according to the cause. For example, bulging in one eye can result from a tumour or infection. Bulging in both eyes is more likely when there’s an underlying illness such as thyroid eye disease.

There can often be other symptoms as well as the change in appearance, including:

Vision problems such as double vision, when swelling restricts movement of the eye muscles. In more severe cases, changes can include blurred vision and trouble with seeing colours clearly.
Red, irritated, and dry eyes due to the cornea being less well protected.
Sensitivity to light.
Eye pain and aching behind the eye, especially if there is an infection or tumour.
Headaches.
Puffy eyelids.

In rare cases, there can be other complications. If the eyelid cannot close to protect the cornea at the front of the eye, it can become more susceptible to infections and ulcers that can cause pain and vision loss. If the optic nerve is compressed, signals from the eye to the brain are affected, which can lead to vision loss. However, vision loss is rare, and prompt diagnosis and treatment can prevent this.

Symptoms can develop slowly, but if bulging eyes develop suddenly, or if there is bulging in just one eye, don’t delay seeing a healthcare professional for medical advice. These can be signs of a serious eye problem or other condition that needs urgent treatment.

If your eyesight is affected, you may need to inform the DVLA, especially if you have problems such as double vision. You may still be able to drive, but you should speak to your ophthalmologist for advice and always follow the DVLA rules.

What causes bulging eyes?

The most common cause of bulging eyes is thyroid eye disease, also known as Graves’ eye disease, especially when both eyes are affected. If symptoms develop suddenly and in just one eye, other potential causes will be investigated, such as eye infection, injury, or tumour.

The most common cause of bulging eyes in adults is thyroid eye disease, also called Graves’ eye disease. The thyroid gland in the neck produces hormones that regulate our metabolism. The thyroid gland can be overactive (hyperthyroidism) or underactive (hypothyroidism). Thyroid eye disease affects one in three people with an overactive thyroid gland (hyperthyroidism) (Source: NHS). Even so, thyroid eye disease is rare - effecting only 16 women and three men in every 100,000 people (Source: Patient) and just 5% experience severe disease that threatens vision loss (Source: Endocrine Reviews).

There are two stages of thyroid eye disease. The first, active phase, causes bulging eyes because the immune system attacks healthy muscle and fatty tissues in the eye socket, causing swelling and pushing the eyeball forward. The inflammation stops in the second inactive phase, but there can be long-term problems due to stretched tissues that may not recover their original shape.
Other less common causes of bulging eyes include:

Tumours, which can be benign or cancerous, including neuroblastoma and soft tissue carcinoma. Other symptoms can include pain, vision changes and eyelid swelling and drooping.

Abnormal blood vessels or bleeding behind the eye, for example, after an eye injury.

Inflammation or infection such as orbital cellulitis, especially when bulging, develops quickly and is associated with pain and fever.

How are bulging eyes diagnosed?

If you notice one or both eyes bulging, see your optician or GP, who may refer you to a specialist eye doctor known as an ophthalmologist. Be ready to tell them about your symptoms and medical history. You may have tests to measure the protrusion of your eyes and find out what the underlying cause is, including:

A dilated eye examination (after taking eye drops to allow closer inspection of your eye).
A visual acuity test.
A slit-lamp exam to look closely at the front of the eye.
A CT scan or MRI scan helps doctors look at the degree of swelling in the eye socket and the areas most affected.
A blood test to check thyroid function by measuring thyroid hormone levels.

If you have Graves’ eye disease, you will probably also see an endocrinologist, a doctor specialising in glands and hormones.

Treatment for bulging eyes

Treatment options differ depending on the cause of bulging eyes. It’s important to get a diagnosis that explains why you have bulging eyes to ensure you have the right treatment plan.

You can ease the symptoms of bulging eyes with some simple steps:

Use eye drops with artificial tears to relieve irritation and dryness.
Sleep in a slightly elevated position by using extra pillows to reduce puffy eyes.
Wear sunglasses on bright days if you’re more sensitive to light.
Get support to stop smoking, which can worsen eye problems.
Try to avoid irritants such as dust and smoke.

The most common reason for bulging eyes is thyroid eye disease, and the underlying thyroid disease needs to be treated. An endocrinologist can prescribe medication to return thyroid hormones to normal levels. Getting thyroid problems under control can help limit inflammation and swelling to prevent damage to the cornea.

If the inflammation is severe and painful, you may need steroids given intravenously over several months. Sometimes, radiotherapy, which uses high energy radiation, reduces swelling.

Eye surgery may be needed if there is pressure on the optic nerve, which can cause permanent vision loss. Orbital decompression surgery removes bone and tissue to make space in the eye socket for the affected tissue, relieving pressure on the optic nerve. This surgery can also help reduce the protrusion of the eyeballs. Some people need surgery on their eyelid or eye muscles to help them work normally again, improving their appearance or correcting double vision.
Different treatment plans are needed for other causes of proptosis. People with cancerous tumours may have surgery to remove the tumour, chemotherapy, radiotherapy, or a combination of these treatments. In cases of infection like orbital cellulitis, infection is treated with antibiotics, and any abscess may need to be drained.

Frequently asked questions

Conclusion

Bulging eyes may be due to an underlying condition that needs treatment. The causes of bulging eyes vary, but thyroid eye disease is most common. If you notice the signs of bulging eyes, see your optician or GP. With the correct diagnosis, bulging eyes can be treated to protect your vision and eye health.

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Medically reviewed by: The Royal College of Ophthalmologists on 28/07/2022

Edited by: Nick Astbury FRCS FRCOphth FRCP
Clinical Associate Professor
LSHTM

The Royal College of Ophthalmologists champions excellence in the practice of ophthalmology and is the only professional membership body for medically qualified ophthalmologists. The RCOphth is unable to offer direct advice to patients. If you’re concerned about the health of your eyes, you should seek medical advice from your GP, optometrist or ophthalmologist.