Null point

In many cases of congenital nystagmus there is a position where the eye movements are slowed right down and narrower, where the eyes are looking in a particular direction in relation to the position of the head. This is called the null point. Either side of the null point the movements typical of nystagmus increase again and the further away the direction of gaze moves the more rapid and more sweeping the eye movements become. It makes sense therefore that the vision is at its best at the null point.

If someone has a null point they will find and use it automatically and are to be encouraged to do so, sitting at the correct angle, for example, in relation to a screen. Unless the null point is when the eyes are straight ahead, others may notice a head turn or tilt. The position of the null point may change from time to time, from one side to the other and back again. Some people nod or shake their heads. Again this is an automatic response to seeking the clearest vision as it may slow the nystagmus or in some way counteract it.