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.