Neuro-ophthalmology
What does it mean if my optic nerve is damaged?
The optic nerve carries all visual information from the eye to the brain, so damage to it reduces vision, colour perception and contrast even when the eye itself looks healthy. Causes include glaucoma, poor blood supply, inflammation, pressure from a swelling, toxic or nutritional causes and inherited conditions. Treatment targets the cause and aims to prevent further loss.
How damage shows itself
- Reduced vision that glasses do not correct
- Colours looking dull or faded, particularly red
- Reduced contrast, so vision seems dim or washed out
- Missing areas in the field of vision
- A pupil that responds less briskly to light on the affected side
Main causes
- Glaucoma, where raised eye pressure damages the nerve slowly and painlessly
- Reduced blood supply to the nerve, which causes sudden painless loss, often noticed on waking
- Inflammation, as in optic neuritis
- Pressure from a swelling or mass behind the eye or in the head
- Raised pressure inside the head, which swells both nerves
- Nutritional deficiency, certain medicines, alcohol and tobacco
- Inherited optic nerve conditions, which may affect other family members
Investigation
Assessment includes vision and colour testing, pupil examination, dilated examination of both optic discs, visual field testing and optical coherence tomography of the nerve fibre layer. Blood pressure, blood sugar, blood tests and imaging of the head and orbits are arranged according to the pattern found.
What treatment can and cannot do
Nerve fibres that have already been lost do not regenerate, so vision already lost is generally not recoverable. Treatment is aimed at the cause, to stop or slow further damage. In glaucoma that means lowering eye pressure. Elsewhere it may mean controlling blood pressure and diabetes, treating inflammation, relieving pressure on the nerve, correcting a deficiency or stopping a responsible medicine, always under the guidance of the clinician prescribing it.
When to seek urgent assessment
- Sudden loss of vision in one eye, which needs assessment the same day
- Vision loss with severe headache, scalp tenderness or pain on chewing, which needs emergency assessment
- Progressive loss over days to weeks
Frequently asked questions
- Can a damaged optic nerve be repaired?
- Lost fibres cannot currently be replaced or regrown. This is why the focus is on finding the cause quickly and protecting the fibres that remain.
- Will glasses help?
- Glasses correct focus, not nerve function, so they do not restore vision lost to optic nerve damage. Magnifiers and lighting can make tasks easier.
Concerned about these symptoms?
Arrange an eye examination with our consultant ophthalmologist in Garki, Abuja.
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