A new study by a team of researchers at the University of Melbourne, published in January 2022, set out to assess the effect, if any, of nystagmus on the perception of movement. Scientists also sought to establish whether those effects changed when the null point was in play.
People with nystagmus were tested both using their null point and not using it. People without nystagmus were tested using both their central gaze and an off centre gaze. They were presented with movement both up and down and side to side.
Their conclusions?
The trial showed that incoherent motion perception (seeing the general direction of movement, such as when a flock of birds is in flight or a crowd of people walking in the street) was impaired in those participants who had congenital or infantile nystagmus, to the same degree in both the horizontal and vertical directions.
The null position was not found to provide significantly better motion perception, although there was a trend towards better horizontal perception at the null position than 15 degrees away from it.
The findings could help to understand better how people with nystagmus perform daily visual activities and assist in developing new clinical visual function assessment tools for nystagmus patients. Compared to static visual acuity, motion perception can be examined to assess the real-life visual function of nystagmus more thoroughly. Questions related to visual motion perception can also be added to quality of life surveys to assess more closely real-life related visual function in nystagmus.
