Protrusion is the protrusion of the eyeball. Clinically, there are many causes of protrusion, mainly due to the following: 1. thyroid disease, especially hyperthyroidism, which is caused by the autoimmune reaction of the patient, manifesting as hypertrophy of the eye muscle, edema of the tissue behind the eye, and mucin deposition, resulting in protrusion of the eye, reduction of transient eyes, widening of the eye fissure, etc. The protrusion caused by hyperthyroidism can manifest as unilateral protrusion, or as bilateral protrusion. 2. postorbital tumors, etc. The human orbital volume is limited, and postorbital tumors can cause protrusion of the eye, especially in patients with unilateral protrusion, and postorbital tumors must be excluded. 3. others, such as congenital protrusion due to abnormal development of the orbital maxilla, and protrusion of the eye due to high myopia, etc.