Conjugate gaze palsies are neurological disorders affecting the ability to move both eyes in the same direction.
[citation needed] A lesion, which is an abnormality in tissue due to injury or disease, can disrupt the transmission of signals from the brain to the eye.
This is where the cranial nerve VI leaves on its way to the Lateral rectus muscle, which controls eye movement horizontally away from the midline of the body.
The cranial nerve VI also has interneurons connecting to the medial rectus, which controls horizontal eye movement towards from the midline of the body.
Nerve VI has the longest subarachnoid distance to its target tissue, making it susceptible to lesions.
[7] The paramedian pontine reticular formation(PPRF), also in the pons is responsible for saccadic movement, relaying signals to the abducens nucleus.
Although more rare than horizontal, one-and-a-half syndrome from damage to the paramedian pontine reticular formation and the medial longitudinal fasciculus can be shown to affect vertical gaze.
However, sometimes a patient exhibits an abduction nystagmus in both eyes, indicating evidence of a conjugate gaze palsy.
Horizontal gaze palsies are generally caused by a lesion in the brain stem and connecting nerves, normally in the pons.
HGPPS is caused by a mutation in the ROBO3 gene, which is important in cross-over of motor and sensory signals, preventing horizontal eye movement.
[17] Stroke victims with conjugate gaze palsies may be treated with intravenous therapy if the patent presents early enough, or with a surgical procedure for other cases.
[18] The prognosis of a lesion in the visual neural pathways that causes a conjugate gaze palsy varies greatly.