Motility disorders that demonstrate typical features of a particular syndrome.
Congenital Cranial Dysinnervation Disorders with Ocular Motility Abnormalities
Duane syndrome: A congenital motility disorder, usually unilateral (85%), characterized by limited abduction, limited adduction, or both. The globe retracts and the eyelid fissure narrows on adduction. An upshoot or downshoot may also be seen on attempted adduction, due to vertical slippage of the lateral rectus. In unilateral cases, the strabismus will be incomitant and the patient will often adopt a face turn to allow them to use both eyes together. Sporadic cases may be associated with skeletal, auricular, and neural deficits. Classified into three types:
Type 1 (most common): Limited abduction. Primary position frequently esotropia. In unilateral cases, nearly always with face turn toward affected side.
Type 2 (least common): Limited adduction. Primary position usually exotropia. In unilateral cases, often with face turn away from affected side.
Type 3: Limited abduction and adduction. Esotropia, exotropia, or no primary position deviation. Significant globe retraction.
Synergistic divergence: A rare motility disorder often categorized as a type of Duane syndrome with poor/palsied adduction. On attempted adduction, the involved eye abducts even further increasing the exotropia. Associated with COL25A1 mutations.
Brown syndrome: A motility disorder characterized by limitation of elevation in adduction. Elevation in abduction is normal. Typically, eyes are aligned in primary gaze, although a vertical diplopia with chin-up head position or face turn can be present. Usually congenital, but may be idiopathic or acquired secondary to trauma, surgery, orbital tumors, or inflammation in the area of the trochlea. Bilateral in 10% of patients.
Monocular elevation deficiency (double elevator palsy): Congenital. Unilateral limitation of elevation in all fields of gaze secondary to restriction of the inferior rectus or paresis of the inferior oblique and/or superior rectus. There may be hypotropia of the involved eye that increases in upgaze. Ptosis or pseudoptosis may be present in primary gaze. The patient may assume a chin-up position to maintain fusion if a hypotropia in primary gaze is present.
Möbius syndrome: Rare congenital condition associated with both sixth and seventh cranial nerve palsies. Esotropia is usually present. Limitation of abduction and/or adduction. A unilateral or bilateral facial nerve palsy is either partial or complete. Other cranial nerve palsies as well as deformities of the limbs, chest, and tongue may occur.
Congenital fibrosis syndrome: Congenital group of disorders with restriction and fibrous replacement of the extraocular muscles. Usually involves all of the extraocular muscles with total external ophthalmoplegia and ptosis. Most commonly, both eyes are directed downward, so the patient assumes a chin-up position to see. Genetic testing is recommended in patients with suspected congenital fibrosis syndrome.
History: Age of onset? History of trauma? Family history? History of other ocular or systemic diseases?
Complete ophthalmic examination, including alignment in all fields of gaze. Note head position. Look for retraction of globe and narrowing of interpalpebral fissure in adduction (common in Duane syndrome).
Pertinent physical examination, including cranial nerve evaluation.
Radiologic studies (e.g., MRI or CT scan) may be indicated for acquired, atypical, or progressive motility disturbances, especially if associated neurologic or developmental abnormalities.
Forced duction testing is used to differentiate the two etiologies of monocular elevation deficiency (test will be positive with inferior rectus fibrosis and negative with superior rectus and inferior oblique paresis). Forced ductions can also confirm the diagnosis of Brown syndrome.