Optic neuritis is an inflammation that damages the optic nerve, a bundle of nerve fibres that transmit visual information from your eye to your brain. Optic neuritis usually affects one eye. Symptoms might include pain, vision loss in one eye, visual field loss, and loss of colour vision or flashing lights. The exact cause of optic neuritis is unknown. It's believed to develop when the immune system mistakenly targets the substance covering your optic nerve (myelin), resulting in inflammation and damage to the myelin.

Optic neuritis is linked to multiple sclerosis (MS), a disease that causes inflammation and damage to nerves in your brain and spinal cord and Neuromyelitis Optica. Most people who have a single episode of optic neuritis eventually recover their vision. Treatment with steroid medications may speed up vision recovery after optic neuritis

Please get in touch with your eye doctor if you develop new symptoms, such as eye pain or a change in your vision, or if your symptoms worsen, or you have unusual symptoms, including numbness or weakness in one or more limbs, which can indicate a neurological disorder.

The factors that have been linked to the development of optic neuritis include bacterial infections, Lyme disease, cat-scratch fever, syphilis, or viruses, such as measles, mumps and herpes. Diseases such as sarcoidosis and lupus can cause recurrent optic neuritis and some drugs like quinine have been associated with the development of optic neuritis.