The cause of<unk>  is unclear in most cases. It may be neurogenic in origin, due to a dysgenesis of the CN IV nucleus or<unk> , but a clinically similar<unk>  may result from absence or mechanical dysfunction (e.g., abnormal laxity) of the superior oblique tendon. Usually unilateral,<unk> es can also occur bilaterally. Bilateral<unk>  may be unmasked only after corrective surgery of one eye for what was thought to be a unilateral<unk> .
Congenital fourth nerve palsy
Cranio-lenticulo-sutural dysplasia
Choroid plexus tumor
Morning glory disc anomaly
Choroid plexus papilloma
Athetoid cerebral palsy
Tonic tensor tympani syndrome
Choroid plexus cyst