Optic neuritis. Information for patients Ophthalmology

Transcription

1 Optic neuritis Information for patients Ophthalmology

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3 What is optic neuritis? Optic neuritis is a common cause of acute visual loss in young people. The optic nerve is like a cable of electric wires; it consists of more than a million nerve fibres carrying visual information from the eye to the brain. If some or all of the fibres become inflamed, then they will not function properly and vision will become blurred. If many of the nerve fibres are involved, then vision can be very poor, but if the optic neuritis is mild, vision can be minimally affected. For most people with optic neuritis, vision will improve (although not always quite back to normal) without treatment. What causes optic neuritis? In the most common form of optic neuritis, the optic nerve is attacked by the body s overactive immune system. In children, optic neuritis may develop following a viral illness such as mumps or a cold. page 3 of 8

4 What are the symptoms of optic neuritis? Optic neuritis usually develops over a few hours to days. You may notice the following symptoms: Loss of vision in one eye. This may be like a blob of grease in one area or it may affect the whole vision. Vision may be dim, as if lights are turned down. Colours may appear dull or faded. Pain behind the eye, especially when moving the eyes. Vision may temporarily worsen after exercising or a hot bath. Occasionally vision may be affected in both eyes. A careful description of the symptoms is important in diagnosing optic neuritis as often the eye looks completely normal when it is examined by an ophthalmologist. How is optic neuritis diagnosed? Optic neuritis is diagnosed by asking about the symptoms as discussed above and then by examining the eyes. During the examination, the visual acuity is measured on an eye chart. The pupils reaction to light is tested and the inside of the eyes are examined, usually after the pupils have been dilated with drops. Other tests of colour vision and visual field may also be performed. Subsequent blood tests and magnetic resonance imaging (MRI) of the brain may be needed. page 4 of 8

5 Conditions which can be confused with optic neuritis The optic nerve can be affected by other disorders such as a lack of blood supply (termed ischaemia) or trapping along its course. There are also rare genetic conditions that can damage the optic nerves. If there are unusual symptoms or if the optic neuritis is associated with other eye or neurological problems, then further investigation with blood tests or brain scanning may be undertaken to look for these other conditions. How is optic neuritis treated? Fortunately, over 90% of people recover their vision without treatment, usually over a period of weeks to months. Some may have residual washed out vision and have disturbances when exercising or taking a hot bath. This often settles with time. Research has shown that patients who are treated with high dose steroids (methylprednisolone), either by tablet or into a vein, have their vision restored more quickly than those who are not treated. However, both groups of patients ultimately are shown to recover to the same level of vision. Therefore, the small benefit from this treatment needs to be weighed up against the risk of side effects from taking high dose steroids. Steroid treatment is of particular use if the symptoms are severe or distressing or if the change in vision impacts on the ability to function. This may occur, in particular, if there is poor vision for whatever reason in the other eye. What is going to happen to my vision? In most patients vision will return to normal or near normal. A small proportion of patients have significant permanent reduction of vision in the affected eye. page 5 of 8

6 Will I get optic neuritis again? Research has shown that 35 percent of people who had optic neuritis had another episode within 10 years, which may occur in either eye. However, despite this, optic neuritis very rarely causes permanent severe loss of vision in both eyes. Is there a link between optic neuritis and multiple sclerosis? Optic neuritis is associated with multiple sclerosis (MS). In MS there is damage to nerves in other areas of the central nervous system, which are the brain and spinal cord. There is evidence that people who have an acute episode of optic neuritis have about a 60 percent risk of going on to develop MS after 10 years. However, it is important to remember that not everyone who has acute optic neuritis will be diagnosed with MS or will develop MS in the future. Further tests, such as an MRI of your brain and a lumbar puncture, where a sample of fluid is taken by placing a needle in your back, can help in determining in more detail the risk of going on to develop MS. Further help and information page 6 of 8

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8 Produced with support from Sheffield Hospitals Charity Working hard to fund improvements that make life better for patients and their families Please donate to help us do more Registered Charity No Alternative formats can be available on request. Please Sheffield Teaching Hospitals NHS Foundation Trust 2016 Re-use of all or any part of this document is governed by copyright and the Re-use of Public Sector Information Regulations 2005 SI 2005 No Information on re-use can be obtained from the Information Governance Department, Sheffield Teaching Hospitals. PD7836-PIL3245 v2 Issue Date: October Review Date: October 2018