Optic Neuritis
What is Optic Neuritis? Optic neuritis is the most common cause of sudden visual loss among young people.
It is often associated with discomfort in or around the eye, particularly with eye movement. The optic nerve is like a cable of electric wires, and consists of more than one million separate tiny wires or nerve fibres. Each nerve fibre carries a part of the visual information picture (or image) we see to the brain. If some or all of the nerve fibres become inflamed and do not function properly, vision becomes blurred.
What causes Optic Neuritis?
It is not entirely clear though it is generally suspected that autoimmune disease and/or previous viral infection may play a role. In the most common form, the optic nerve is attacked by the body’s overactive immune system. In children especially, optic neuritis develops following a viral illness such as mumps, measles or colds.
What are the symptoms of Optic Neuritis?
Optic neuritis usually develops over a few hours to days. One may notice the following symptoms:
Blurred vision in one eye or both, especially after exercising or a hot bath. The blurring may be like a blob of grease in one area or it may affect the whole picture in one eye.
Vision is dim, as if the lights are turned down.
Colours appear dull or faded.
Pain behind the eye, particularly when moving the eyes.
How is it diagnosed?
The Ophthalmologist will measure your vision, examine how your pupil reacts to light and inspect the inside of your eye.
How is it treated?
Fortunately over 90% of people recover their vision without any treatment, generally 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 is related to the damaged myelin (insulation) that surrounds the nerves. It often settles with time and patients who notice this problem are no more likely to get worse.
Most people who have one will never have another episode, but recurrences (second attacks) can occur, either in the same eye or in the other eye. They are treated in the same way as the first attack.
FREQUENTLY ASKED QUESTIONS
What caused this to happen?
We do not have a complete understanding of optic neuritis. It is likely that it represents a combination of a particular form of immune system reaction with a previous stimulation possibly by a virus.
What is going to happen to my vision?
In the vast majority of patients, your vision will improve. It may not improve to normal, but it is likely that there will be a sustained improvement whether or not you are treated.
Can treatment with steroids make this better?
Treatment with intravenous (drip) steroids has been demonstrated to accelerate recovery but it will not on average change the ultimate level of recovery. We have no way to guarantee that vision will recover and in some patients it will not.
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