In conjugate gaze palsies, the two eyes cannot move in one direction (side to side, up, or down) at the same time.
Conjugate gaze palsies affect horizontal gaze (looking to the side) most often. Upward gaze is affected less often, and downward gaze is affected even less often. People may notice that they cannot look in certain directions.
There are no specific treatments.
Horizontal gaze palsy:
The most common cause is damage to the brain stem, often by a stroke. Often, the palsy is complete and severe. That is, the eyes cannot move to the side at all. Palsies can also be caused by damage to the front part of the cerebrum, usually by a stroke. The resulting palsy may not be as severe as that caused by damage to the brain stem, and symptoms often lessen with time.
Vertical gaze palsy:
Vertical gaze decreases gradually with age, but vertical gaze palsy is more severe than age-related changes. Usually, upward gaze is affected. The most common cause is damage to the top part of the brain stem (midbrain), usually by a stroke or tumor.
The pupils are usually large (dilated). In response to light, they may constrict more slowly and less completely than normal. When people attempt to look up, the eyes rapidly move in one direction, then slowly drift in the other direction. These involuntary, fluttering eye movements are called nystagmus.
If downward gaze but not upward gaze is impaired, the cause is usually progressive supranuclear palsy (see Progressive Supranuclear Palsy).
Last full review/revision September 2012 by Michael Rubin, MDCM