The syndrome was first described by Brown in 1950. Brown’s syndrome was first described in 1950 and was characterized by primary defects of the muscles and their attachment points, with the eyes fixed in a downward gaze state. Etiology: The etiology is not known, but it may be a developmental defect of the muscle and its attachment surface. The sheath of the superior oblique muscle becomes short and attaches to the carriage, forming a nodal ligament that restricts the normal function of the ipsilateral inferior oblique muscle. It is also believed that bleeding at the tendon site after trauma, inflammatory scar contracture and excessive folding of the superior oblique muscle after surgery, in addition to various theories such as adhesions between the tendon and tendon sheath of the superior oblique muscle. Ocular features: 1. Diplopia, which usually occurs when the affected eye is turned inward, the upper eyelid droops, the head is tilted backward, the eye is fixed in a downward gaze, the lid fissure opens wide when lifting up, and the eye is limited in movement in the direction of the superior oblique muscle, often giving the false impression that the superior oblique muscle is paralyzed, and when the same movement is made to the opposite side, the affected eye is downward slanted. Internal retraction and abduction are limited, or completely impaired. Generally, in the original position, there is no obvious strabismus during abduction and downward gaze. 2. When the affected eye is pulled to the internal rotation position under general anesthesia, the eye can be found to be passively turned upward without reaching the limit of voluntary rotation, which often confirms the diagnosis at the time of surgery. 3. Conjunctival elasticity may be reduced with choroidal agenesis. V. Systemic features: abnormal head position is often present. The head tends to be ipsilateral, contralateral between turns, and the lower jaw is elevated. Differential diagnosis: must be differentiated from inferior oblique muscle palsy. Treatment: Surgery should be considered only when the affected eye is obviously hypotropic or has an obvious abnormal head position. Tendonotomy of the superior oblique muscle (temporal incision is appropriate), or partial tendonotomy can be done.