SEP 23, 2016
Divergence insufficiency (DI) is defined as a comitant esophoria or esotropia worse at distance than near (or absent at near), with full ductions and no evidence of cranial nerve palsy.
DI can be secondary to neurologic causes or can be primary (idiopathic). A poorly defined divergence center in the caudal pons is hypothesized to be responsible for neurologic divergence paralysis. More recently, involutional changes within the orbital connective tissue and extraocular muscles have been recognized as non-neurologic causes of distance esotropia in older individuals. Most patients with DI in isolation do not develop future neurologic disease.
The main differential diagnosis of DI is bilateral CN VI palsy, and careful attention to signs of increased intracranial pressure, other cranial nerve involvement, neurologic signs or symptoms, and history of onset after trauma are important. Neurologic workup with imaging or lumbar puncture might be helpful.