Brown's Syndrome in the absence of an intact superior oblique muscle.

Brown's Syndrome was initially described as a superior oblique tendon sheath syndrome-a short anterior tendon resulting in a restricted elevation of the globe in the nasal field. Brown believed that a congenital paralysis of the inferior oblique muscle resulted in this secondary shortening of the anterior sheath of the superior oblique tendon. The definition of Brown's Syndrome has changed over time. It is currently defined as the inability to elevate the eye in the adducted position, both actively and passively on force duction testing, and can be acquired. The pathophysiology of acquired Brown's Syndrome may involve an abnormality of the superior oblique trochlea/tendon complex. However, it may also result from other causes unrelated to the superior oblique tendon or muscle, such as tumors of the superior nasal orbit, inferior orbital mechanical restriction, or an inferiorly displaced lateral rectus muscle and pulley. We present two cases in which a Brown's Syndrome was diagnosed after the superior oblique muscle had been disinserted or removed.