Thyroid eye disease occurs when the muscles and fat in your eye sockets become inflamed and swell. Anyone can develop this condition, especially if you have an overactive or underactive thyroid gland.  It is commonly caused by an autoimmune disease that attacks the normal tissues in the thyroid gland and eyes. Medications, lubricating eye drops, ointments, and other treatments can reduce these symptoms: bulging eyes, redness, dryness, grittiness, light sensitivity, pain, and more.