Brown Syndrome

Brown syndrome can be acquired or congenital and is caused by damage to the trochlea of the superior oblique muscle tendon, an abnormality of the superior oblique tendon itself, abnormalities of the tissue around the rectus extraocular muscles, the rectus pulleys, or a congenital abnormality of the superior oblique muscle itself that results in a restriction present at birth. This tethering effect may cause difficulties with elevation noted early in childhood as the child attempts to fixate on objects in their superior visual field.  Acquired Brown syndrome, on the other hand, may develop secondary to inflammatory processes, trauma, surgery, or systemic conditions such as rheumatoid arthritis. It can vary in presentation and severity, often presenting diagnostic and therapeutic challenges. A pseudo-Brown syndrome is sometimes seen following implant surgery is not due to superior oblique muscle-tendon pathology. For this review, true Brown syndrome is due to a congenital cause, with a constant limitation of elevation and a positive traction test secondary to a tight, superior oblique tendon. The pathophysiology behind Brown syndrome centers on the inability of the superior oblique tendon to move freely through the trochlea, a fibrocartilaginous loop that acts as a pulley. The tendon may be inelastic or have an abnormal course in the congenital variant. Clinically, Brown syndrome is characterized by a triad of features: limited elevation in adduction, widening of the palpebral fissure in attempted upgaze, and a strange head posture adopted by the patient to minimize diplopia and maximize binocular vision. These clinical signs, often associated with a click or snap felt on attempted elevation in adduction, can be pathognomonic. The diagnosis of Brown syndrome is primarily clinical, based on a comprehensive history and detailed ocular examination, including forced duction testing and the assessment of ocular motility. Diagnosis is often challenging; a thorough history and clinical examination are necessary to determine etiology and management. Imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT) may be employed to elucidate the anatomical details in complex cases or when planning for surgical intervention.  Management strategies for Brown syndrome vary from conservative observation to surgical correction, depending on the severity of the condition and its impact on the patient's visual function and quality of life. Non-surgical approaches may include prisms for mild cases or therapeutic exercises. However, in cases where significant abnormal head posture, diplopia, or cosmetic concerns are present, surgical intervention might be considered. Surgical options typically aim to lengthen or alter the course of the superior oblique tendon to alleviate the restriction. Brown syndrome poses unique challenges regarding its impact on the visual axis and patients' psychosocial well-being. The condition can be isolating and functionally limiting, particularly in cases where compensatory head postures are significant. This review seeks to explore the intricacies of Brown syndrome, discussing its etiology, clinical features, diagnostic approaches, and management options, emphasizing the latest advancements in treatment and patient care. In 1949, Dr. Harold Brown first described 8 cases of a new ocular motility condition, which presented with restricted elevation in adduction, among other features. The clinical features were similar to those of an inferior oblique palsy, except that superior oblique muscle overaction was minimal. During surgery, Brown discovered a shortened tendon sheath of the superior oblique muscle tendon, which was thought to restrict passive elevation movement in the adducted field. Hence, the initial name "superior oblique tendon sheath syndrome" was used. After extensive further investigation, it was demonstrated that key clinical features were a V or Y pattern strabismus, divergence in upgaze, downdrift in adduction, and a positive forced duction test (also known as a traction test) for ocular elevation in the nasal field. The condition, Brown syndrome, has since been recognized as a significant cause of vertical strabismus, with implications for both binocular vision and quality of life.