Ocular dipping

Ocular dipping is an abnormal eye movement consists of cycles of eye movements occurring spontaneously, that are characterized by a slow conjugated downward deviation followed after a delay by a quick return to mid position. 

Periodic slow downward movements followed by fast Upward movement  to the primary position
Slow down-fast up
It is also called as inverse ocular bobbing
Causes of ocular dipping

• Ocular dipping is only described in unconscious patients, especially those in anoxic coma
• Diffuse or multifocal encephalopathies 
• Diffuse structural brainstem damage.
• Creutzfeldt-Jakob disease.

Spontaneous eye movements are useful clinical signs in coma, although they rarely have localizing value. The best-known exception to this rule is ocular bobbing,that is found in pontine lesions.