Bulging eyes may be caused by eye diseases, excessive thyroid hormones and high myopia. 1. Eye diseases: Inflammation, edema, tumor, trauma, and cavernous sinus thrombosis of the eye socket or enlargement of the eyeball, such as congenital glaucoma or high myopia may cause bulging of the eyeballs, resulting in dryness of the cornea, infections and ulcers. 2. Excess thyroid hormone: Patients with thyroiditis will secrete too much thyroid hormone, causing the sympathetic nerves in the body to be in a constant state of excitement, which affects the function of the extraocular muscles, causing the upper eyelid to retract, resulting in bulging out of the eyeballs. Patients will have obvious symptoms such as eye swelling, eye pain and photophobia. 3. High myopia: High myopia will cause the eye axis to be longer, which will make the eyeballs appear larger, and the symptoms of bulging out of the eyeballs will appear. When the patient appears to have symptoms such as eye swelling, eye pain, frequent tearing, etc., it is recommended to go to the hospital in time for examination and treatment under the guidance of the doctor.