Labyrinthine nystagmus (n.labyrinthicus) in ophthalmology is usually called a rare, but dangerous, congenital defect - damage to retinal ganglion cells. Disturbances form an increased level of tension (hyperreflexia) in the fibers of the muscle that turns the eyes to the side. The result of this is that the eyes are held for a long time (the eyes look in one direction all the time, and nystagmus fluctuations are very weakly expressed).