The door as seen
by someone with
The door as seen
by someone with severe nystagmus
Characteristics. Nystagmus is characterised by an involuntary movement of the eyes. There are various types of Nystagmus. (I have what is known as Congenital Idiopathic Nystagmus and I am registered partially sighted).
Visual acuity. Most people with Nystagmus have a visual acuity way below short sight. Many are partially sighted; some are registered blind; few can drive a car. Most sufferers encounter practical and social difficulties, although these can be so well concealed that other people are little aware.
Co-ordination and balance. Depth of field vision is reduced and balance is affected, with the result that sufferers may be prone to tripping and are likely to struggle with tasks that require hand eye co-ordination.
Causes. Nystagmus may be inherited or result from a sensory problem. In some cases it occurs for no known reason. It can also develop in later life, sometimes as a result of a head injury, accident or a range of illnesses.
Effects. Nystagmus affects people in different ways, including:
• Difficulty maintaining eye contact
• Appearing to look beyond a person
• Inability to ‘read’ faces, especially at a distance
• Problem reading some letters more than others
• Reduced reading speed due to slow scanning
• Inability to share a book because of distance or angle
• Tiredness due to concentration required in focusing
• Poor sense of balance
• Dizziness when climbing stairs
• Dizziness and disorientation in crowds
• Difficulty telling whether traffic is moving or stationary
• Problem focusing on moving objects
• Difficulty with hand eye co-ordination
• Head tilt due to 'null point'
• Back and neck problems resulting from head posture.
Glasses or contact lenses. Nystagmus affects the nerves behind the eye rather than the eye itself and hence correction is not possible. Glasses are often worn to correct other vision problems which accompany Nystagmus.
Varied vision. Vision can vary considerably during the day. It is also likely to be affected by emotional and physical factors such as being in unfamiliar surroundings, stress, tiredness, or nervousness.
Angle of vision. Most sufferers have a 'null point' where eye movement is reduced and vision improved, which means it might be easier to see one way or the other. A head tilt may be developed to make best use of vision and there may be slight shaking of the head in an attempt to focus.
Misunderstandings. The misunderstandings that arise through Nystagmus can be upsetting for sufferers and the lack of understanding of others and the isolation experienced by the sufferer can, at times, be more problematic and distressing than the visual disability itself.
For more information visit www.nystagmusnet.org