The Optic Nerve
The optic nerve leads from the back of the eye to the brain sending electrical impulses converted from the light entering the eye in to images for the brain to interpret.
What is Optical Neuritis (ON)?
Optical neuritis is the inflammation of the optic nerve, which can cause partial or full vision loss. In some people this condition is an early indication of multiple sclerosis, which causes inflammation and damage to the nerves in the brain and spinal cord.
Symptoms of Optical Neuritis
The symptoms can involve loss of colour vision, washed out images and pain in the eye. This condition can develop in just one eye, or both at the same time or alternatively.
PAIN: There is normally pain associated with ON, which increases when there is eye movement.
VISUAL LOSS: Vision loss varies with individuals. Some experience vision loss severely and have blurred or washed out vision whereas others may not notice any change at all. Vision loss can occur from between one day to a week which can temporary but in some cases become permanent.
LOSS OF COLOUR VISION: Red and Green colours can be affected can be affected where the image look less sharp and the colour looks dull.
Optic Neuritis can happen occur quite quickly and can develop over the course of a few hours, and some have complained that they have woke up with blurred vision but it is more common for it to develop over several days.
Who is at Risk of Optic Neuritis
Optic neuritis can affect people of any age, however those more prone to this condition are:
AGE: those between the age of 15 - 50.
GENDER: Twice as likely to occur in women.
RACE: Caucasians are more likely to suffer from Optical Neuritis.
Studies have shown that those that have ON develop autoimmune disease, multiple sclerosis (MS), after 15 years, different studies show varying results of correlations, between ON and MS and ON is considered one of the earliest signs of MS.
Causes of Optic Neuritis
As explained above electrical impulses travel through the optic nerve to allow the brain to convert the impulses into images in the brain.
The optic nerve is a number of nerves covered in a myelin sheath, a fatty tissue, that allows the electrical impulses to travel quickly to the brain. In two autoimmune conditions this fatty tissue is attacked, which causes the optic nerve to become inflamed and damaged.
MULTIPLE SCLEROSIS: This condition involves the body attacking the myelin sheath of the nerves in the brain and spinal cord. As stated above those that have ON, 50% of cases where ON was developed MS was developed after 15years.
NEUROMYELITIS OPTICA / DEVIC'S SYNDROME: This condition is affects the central nervous system, which in turn affects the spinal cord and the optic nerve. Again, the body attacks the myelin sheath surrounding the optic nerve and spinal cord.
There are a number of other causes that cause Optic Neuritis.
INFECTIONS: Infections or viruses can cause ON, for example syphilis, HIV, hepatitis B or herpes.
DIABETES: People that have diabetes are at an increased risk of developing ON
CRANIAL ARTERIES: This is the inflammation of the arteries in the brain, which can lead to restriction of blood flow to the brain and the eyes. Any problems in the blood flow can cause stroke or vision loss.
Optical Neuritis is usually diagnosed when you have a sight test after the patient has complained of eye pains or vision deficiencies. The optometrist who checks your sight carries out a routine eye exam together with specific tests to investigate the patients concerns. The optometrist will refer you to an ophthalmologist to diagnose and treat the condition. You may also be referred to your GP to investigate any possible autoimmune diseases.
It is imperative that regular eye test is carried to determine what your vision should be, if you notice any change in your eyesight you should have it checked as early as possible.
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