Optic nerves carry information from the eyes to the brain. Damage caused to the optic nerves disrupts the vision of the eye, and is termed optic neuropathy. It can occur from a lack of blood supply to the nerves. Some of the other causes of nerve damage may include radiation, trauma, glaucoma and conditions of the brain such as a tumour, multiple sclerosis and stroke.
The symptoms associated with this condition include loss of vision over a period of time in one or both eyes – severe cases may be characterised by complete blindness. The pupil’s ability to react to light is reduced and colours look faded.
Optic neuropathy can be diagnosed by a thorough examination of the eye which includes:
- Tonometry (measurement of eye pressure)
- Visual acuity (test to assess vision)
- Colour vision (test to asses perception of vision)
- Pupil light reflex (test the eye’s reflex to light)
- Automated perimetry (visual field testing)
- Imaging tests such as MRI and CT scans (to identify orbital or intra-cranial lesions)
The damage to the optic nerve cannot be reversed. Further loss of vision and blindness can be prevented by treating the underlying condition.