The thyroid gland, located in the front of the neck, produces hormones that help regulate the metabolism of the body (the process in which the body transforms food into energy). In a small number of people, the thyroid gland malfunctions and produces more hormones than the body needs. This is called hyperthyroidism, or Graves’ disease. Patients with hyperthyroidism may have any of the following symptoms:
• neck swelling
• intolerance to heat
• increase in appetite and loss of weight
• anxiety, nervousness
How does Graves disease affects the eyes?
Graves’ disease can affect the eyes in many different ways. The symptoms may vary from person to person. Many patients start experiencing eye problems as soon as their thyroid gland becomes overactive. For some the eye changes may develop before hyperthyroidism is detected, while others may not develop symptoms until months or years later. Both eyes are usually affected, however they may not be affected to the same degree.This condition tends to affect middle aged women.
Following are several common eye problems associated with the disease:
Eye protrusion. The excess hormones in Graves’ disease cause the muscles in and around the eye to swell and push the eye forward. This eye bulge is a characteristic symptom of Graves’ disease and causes patients to look as if they are constantly staring.
Eyelid retraction. The combination of eyelid swelling and eye protrusion may cause the eyelids to retract and reveal the white parts of the eye above and below the iris.
Dry eye. Due to eye protrusion and eyelid retraction your eyes are more exposed to environment elements, such as wind and may become very dry. Dry eye can cause several side effects including:
• irritation and discomfort of the eye
• inflammation of the eye
• excessive tearing
• light sensitivity
• blurred vision
• ulcers on the cornea (the clear front window of the eye)
• scarring of the cornea
• vision loss
Double vision. Muscle swelling may cause double vision. It may occur constantly or only when looking in certain directions. Prolonged and excessive muscle swelling can also compress and damage the optic nerve (the nerve in the eye that sends visual impulses to the brain) and cause blindness.
Eye “bags”. Eyelid swelling can also cause fatty tissue around the eyes to bulge forward. This causes the appearance of “bags” around the eyes and can make patients look prematurely aged.
It is common for thyroid eye disease to fluctuate within the first few years of the disease. It is important for you to be seen and treated by an ophthalmologist throughout this period. Beyond this time, the disease tends to stabilize. Many patients will be left with some degree of protrusion, lid retraction, or double vision that may require additional treatment.
How are eye and vision problems treated?
Your ophthalmologist will monitor eye protrusion and retraction by taking precise measurements of your eyes. If the measurements are increasing, also your symptoms are getting worse, treatment maybe needed. A combination of non-surgical and surgical methods may be used to treat your symptoms.
Non-surgical treatment options may include:
• applying lubricating ointment and/or artificial tears to relieve some symptoms of dry eye
• elevating your head at night to reduce muscle swelling
• applying cool compresses to the eyes to relieve the discomfort associated with eye irritation and inflammation
• wearing sunglasses to relieve light sensitivity
• using eyeglasses with prisms to reduce double vision
• taking steroid medications or other immunosuppressive agents to control the eye muscle swelling and inflammation
• radiation is an effective way of reducing swelling of tissue around the eye and relieving compression of the optic nerve. The dose used is very low and thus very safe.
Surgical treatment options may include:
• repositioning the eyes to allow them to move back into a more normal position in the eye socket (orbital decompression)
• repositioning the eye muscles to relieve double vision
• adjusting the position of retracted eyelids to improve closure and restore function. Removal of excessive fat from the eyelids can also improve their appearance (blepharoplasty).
• relieving compression on the optic nerve to preserve sight
More about the surgical treatment of thyroid eye disease
Surgery is generally reserved for quiescent (inactive) disease, once inflammation has settled. The exception is urgent orbital decompression for loss of vision caused by compression of the optic nerve (optic neuropathy).
Thankfully, modern medical therapy has made emergency decompression rare. If orbital decompression is needed, it is performed first to bring the eye back into the socket.
Orbital decompression involves expanding the bony walls of the eye socket (orbital cavity) and is often combined with removal of some orbital fat. This decreases protrusion of the eye and reduces pain and discomfort.
The technique involves minimally invasive surgery, usually through a small skin-crease incision. The most common complication is of new or worsening pre-existing double vision, known as diplopia. This has been reported in up to 15 per cent of cases.
Double vision that persists may be either controlled with prisms or require eye muscle surgery (strabismus surgery) in order to align both eyes better. This is usually performed as day case surgery.
Eyelid surgery is then available to improve the staring look, if this persists. Upper and lower eyelid lifts (blepharoplasty) remove any excess skin and fat slippage, or prolapse, from the eyelids.
What are the risks and complications?
Minor bruising or swelling may be expected and will likely go away in one to two weeks. Bleeding and infection, which are potential risks with any surgery, are very uncommon. As with any medical procedure, there may be other inherent risks that should be discussed with your surgeon.
Is the surgery effective?
While it may not be possible to completely eliminate all of the consequences of thyroid eye disease, surgery to correct these conditions is generally successful in satisfactorily restoring function, comfort, and cosmetic appearance.