Nystagmus that develops later, generally in adults, is called “acquired nystagmus”. Often acquired nystagmus is a sign of another (underlying) condition such as stroke, multiple sclerosis, brain tumor, the effect of a drug or a head injury. Anything that damages the parts of the brain that control eye movements can result in nystagmus.
How is acquired nystagmus diagnosed?
Acquired nystagmus can be caused by a disease (brain tumor), an accident (head injury), or a neurological problem (side effect of a medication). Hyperventilation, a flashing light in front of one eye, nicotine and even vibrations have been known to cause nystagmus in rare cases.
Acquired nystagmus can be clinically investigated by using a number of non-invasive standard tests, and these include using an eye tracker machine.
How is acquired nystagmus treated?
The understanding of nystagmus and the treatments for the condition are developing all the time. Those which are available include: botulinum toxin injections; drugs (such as Gabapentin and Memantine reduce the effects of acquired nystagmus in some people although they do have some side effects); and surgery which can move the null point and possibly improve vision.
Various alternative therapies have been tried by people with nystagmus and although there is no scientific evidence that they work, some people say they have led to improved vision or even cured nystagmus in individual cases.
How does acquired nystagmus affect vision?
The main effect of acquired nystagmus is the sense that things are always moving (oscillopsia). Unlike in congenital nystagmus where the brain somehow adapts to the eye movement, giving a generally still image, this is not usually the case with acquired nystagmus.
For this reason acquired nystagmus can sometimes be a more disorienting form of nystagmus than congenital nystagmus.
Can acquired nystagmus be cured?
Unfortunately, a cure has yet to be found for nystagmus in general, however research work is constantly being undertaken to better understand the condition so that an effective treatment can be identified. The main issue is that knowledge is developing rapidly about the underlying problems with the visual system that lead to nystagmus. Correcting problems in the eye without risking what good sight there is presents doctors with an immense problem.
In general, the main way in which doctors can help is to alleviate symptoms and provide information. This includes correcting any other issues, such as short or long sight, astigmatism or squint.