Thyroid Disease Problems in the Eye

Baltimore Washington Eye Center, Maryland

Friday, August 19, 2011

Thyroid Disease Problems in the Eye

Not everyone with thyroid problems develops eye disease, but a high percentage of people with thyroid abnormalities will eventually have eye issues.  It could be something as simple as dry eye, or something much more visually significant, like double vision and proptosis (eye bulging), or it could be vision threatening, like compressive optic neuropathy.  These eye changes can be seen in people with all types of thyroid disorders. Most commonly, they develop in patients who are or were hyperthyroid (overactive thyroid) and most often within the first year of diagnosis. However, eye problems can occur in patients who have an underactive or even normal thyroid function.

What can often be confusing for patients is the fact that the severity and progression of the eye disease is not necessarily correlated with the levels of thyroid hormones.  The thyroid function may be completely controlled and the patient can still see progression of eye disease.

We don't really understand the entire process behind thyroid eye disease, but we do know that it is auto-immune. The immune system reacts to the patient’s thyroid gland cells and causes thyroid hormone abnormalities. This same immune system reaction is also noted in the eye muscles and orbital soft tissue. Inflammatory white blood cells called lymphocytes and fibroblasts cause enlargement of the eye muscles and accumulation of fluid and inflammation in the orbital fat. This process can lead to the development of eye discomfort and proptosis due to the extra pressure on the eye from enlarged eye muscles and orbital fat. Eyelid retraction can be caused by abnormalities to the eyelid muscles and double vision can be caused by asymmetry of the muscles and abnormality of muscle function.

It is important to make sure that the thyroid function is well controlled, because even though thyroid eye disease can progress in the face of normal thyroid function, abnormal thyroid function increases the risk that eye problems will develop.  So it is vital to have a good relationship with your primary care physician and endocrinologist. However, one of the most important things you can do to prevent or improve thyroid eye disease is to stop smoking, if you are a smoker. Studies have shown that patients with thyroid eye disease will exacerbate their problems if they smoke. Furthermore, patients who stop smoking, often see an improvement in their thyroid eye disease.