Acquired bilateral superior oblique palsy following severe head injury is characterized by a disabling torsional diplopia, with a right hypertropia present in gaze down left, and a left hypertropia present in gaze down right. It is caused by a hemorrhage in the roof of the midbrain at the caudal end of the quadrigeminal plate. This is the area of the decussation of the fourth cranial nerve. The condition may go unrecognized by the clinician if the palsy is equal in the two eyes in which case there may be little or no deviation present on cover test in the primary position. Testing of the cardinal fields and diplopia field testing reveals the underaction of each superior oblique, and the resultant hypertropia with extorsion. Spontaneous improvement of superior oblique function of each eye often occurs in these cases. Occasionally only one superior oblique recovers completely and the resolution of the condition is a residual unilateral palsy.