The fourth cranial nerve controls the superior oblique muscle. So weakness of the nerve
is also known as “Superior Oblique Palsy”. Weakness of this muscle causes a
combination of vertical, horizontal, and torsional misalignment of the eyes. The vertical
misalignment is typically the most noticeable feature.
Superior oblique palsy may cause double vision either vertically or diagonally. Diagonal
double vision is where both the vertical and horizontal are affected. Usually if the patient
has had superior oblique palsy since birth (congenital), a head tilt may be the only
symptom.
Symptoms of acquired superior oblique palsy can be dizziness, trouble reading, blurry
vision at distance and near, light sensitivity. An acquired superior oblique palsy can be
from head trauma, even mild head trauma such as a concussion can cause superior
oblique palsy. Motor vehicle accidents can cause superior oblique palsy.
Some patients who have a traumatic incident occur can have it spontaneously resolve
within 6 months. About 10-15% of patients experience persistent symptoms after 6
months. In this case, treatment with prism is highly effective – usually around 80%.