This nerve connects the retina to the brain.
Each nerve carries 1 million fibers, most come from the macula.
Damage to the nerve causes a central defect in the visual field , reduced brightness and colour and an impairment of the pupil reflex, when compared with the normal eye.
The retina catches the focused picture like a projection screen. It then codes it into electrical messages which are carried in the optic nerve to the brain. These electrical signals are relayed to the seeing part of the brain (visual cortex) this is found at the back of the head (occipital cortex).
The visual cortex makes sense of the electrical signals so that we see.
If the nerve is sick, the wrong signals are received by the brain.
The nerve can be effected by poor development, glaucoma, head or eye injury, multiple sclerosis, tumours, poor blood flow such as in inflammations or blockages of the artery, diabetes, thyroid disturbance, vitamin deficiencies and drug or alcohol toxicity, and others.
This information site has been provided by varied UK and US eye doctors for patients with eye problems.
Once your eye doctor has made a diagnosis or recommended an investigation or treatment, then you will be able to find further explanation on this site.
It is not a self diagnosis centre. It should not be relied upon without taking professional advice.