Non-infiltrative proptosis usually does not cause diplopia; diplopia should be considered to be caused by strabismus and posterior scleritis. Proptosis is a common clinical symptom of hyperthyroidism, which is categorized into non-infiltrative protrusion and infiltrative protrusion according to the different clinical symptoms of patients. Patients with non-infiltrative synophthalmos usually have mild protrusion of the eyeballs, decreased blinking, upper eyelid contracture and other symptoms, and usually do not have diplopia. Patients with thyroid disease who have their own underlying ocular conditions such as strabismus, posterior scleritis, or a history of orbital fracture can develop diplopia. Patients with non-infiltrative synophthalmos due to hyperthyroidism who present with diplopia need to be considered as a result of the above factors. It is recommended that patients with non-infiltrative synophthalmos and diplopia should consult a doctor as soon as possible for examination to identify the specific cause, and then treat hyperthyroidism and diplopia under the guidance of the doctor.