Treatment and diagnosis of congenital fourth nerve palsies: an update

Purpose of review This review discusses recent advances in our understanding of the pathology, diagnosis, and treatment of congenital fourth nerve palsies. Recent findings High-definition MRI, which can now more accurately image the trochlear nerve, has increased our understanding of the pathology of fourth nerve palsies. A more sensitive two-step test is proposed to replace the three-step Parks–Bielschowsky test. Procedures strengthening the superior oblique tendon can be performed with a low incidence of secondary Brown syndrome. Summary Recent MRI studies have shown two pathological mechanisms associated with congenital superior oblique palsies. Superior oblique tuck combined with inferior oblique recession is a very effective way of eliminating head tilt secondary to congenital fourth nerve palsies.