Thyroid problems can cause blurred vision. From physiological aspect, the disorders of people's face and head can have an effect on eyes, because they have common blood vessels, nerves, lymph and other tissues. Thyroid belongs to the whole body systemic disease, which can naturally affect the visual function. If it is accompanied by hyperthyroidism, it will cause exophthalmos, thyroid associated ophthalmopathy is the most common disease of eyes, and it is included into autoimmune diseases. And even the thyroid function is normal, it also can cause orbital diseases. Thyroid associated ophthalmopathy is a common reason which cause unilateral exophthalmos and binocular exophthalmos.