Impaired or loss of vision | Nuffield Health

What causes loss of vision?

Sudden visual loss usually has an underlying cause affecting your eye, its blood supply, or the nerves connecting your eye to your brain. Common causes include:

Retinal detachment – when the light-sensitive layer at the back of your eye pulls away from its supporting tissue
Acute glaucoma – a rapid build-up of fluid and pressure inside your eye, which can damage the optic nerve
A blockage in the blood vessels supplying your retina or optic nerve, cutting off oxygen to your eye
Age-related macular degeneration, sometimes with bleeding into the retina
Optic neuritis – inflammation of the nerve that carries signals from your eye to your brain
A stroke or mini-stroke (transient ischaemic attack) affecting the visual pathway in your brain
Eye injury or infection inside the eye.

You're more likely to be at risk if you have diabetes, high blood pressure, a smoking history, high levels of short-sightedness (myopia), or a family history of glaucoma or retinal disease.

Gradual vision loss, developing over months or years, is usually caused by a different set of conditions and doesn't call for the same emergency response as sudden loss.

Are there different types of vision loss?

Vision loss is generally grouped by how quickly it develops and how much of your sight it affects:

Sudden vision loss: Develops within seconds, minutes or a few days, and is always treated as a medical emergency
Gradual vision loss: Develops slowly over months or years, and is usually linked to a different set of causes
Vision loss can also affect one eye or both: And can mean losing all vision or just part of your visual field, such as your central vision or your side (peripheral) vision.

How is loss of vision diagnosed?

Because sudden vision loss is a medical emergency, diagnosis usually starts straight away in an emergency department or eye clinic. A doctor will ask when your vision changed, whether you have pain, whether you've had an eye injury, and whether you see floaters or flashes of light, alongside your general medical history.

You'll usually have an eye examination, including checking how well you can see (your visual acuity), examining the back of your eye after using drops to widen your pupil, and measuring the pressure inside your eye.

Further tests may include optical coherence tomography (OCT), which takes a detailed cross-section image of your retina, visual field testing to map any areas of lost sight, and blood tests to check for inflammation, blood sugar or cardiovascular risk factors. If a brain-related cause is suspected, you may also need a CT or MRI scan.

How is loss of vision treated?

Treatment depends entirely on what's causing your vision loss, and starting it quickly gives you the best chance of recovering your sight. Options can include:

Eye drops, tablets or injections: Including steroids to reduce inflammation or medicines to lower pressure inside your eye
Anti-VEGF injections: These are used for conditions such as wet age-related macular degeneration
Urgent surgery or laser treatment: For example to repair a detached retina or a retinal tear
Treatment for an underlying condition: Such as diabetes or high blood pressure, alongside medicines to reduce your risk of a further stroke.

If your vision doesn't fully return, low-vision aids and rehabilitation support can help you make the most of the sight you have left, and psychological support is also available to help you adjust.

When should you see a doctor?

Sudden vision loss is always a medical emergency, even if it's painless or your vision comes back quickly. Call 999 or go to your nearest emergency department straight away if you have sudden loss of vision in one or both eyes, a new dark shadow or curtain across your sight, flashing lights, or severe eye pain with nausea and blurred vision.

If your vision is changing more gradually, such as slowly worsening central or side vision, straight lines or colours looking distorted, or needing to update your glasses prescription more often than usual, book an urgent appointment with an optometrist or GP rather than waiting for your next routine check-up.

FAQs

Is sudden vision loss always an emergency?

Yes. Even if the loss of vision is painless, or your sight seems to be returning, it can be a sign of a serious problem such as a retinal or blood vessel problem that threatens permanent damage. Seek emergency care straight away rather than waiting to see if it improves.
Can lost vision be recovered?

Sometimes. Vision often returns if the underlying cause, such as a retinal tear or inflammation of the optic nerve, is treated quickly. Long-standing damage is harder to reverse, but low-vision aids and rehabilitation support can help you make the best use of any remaining sight.
How often should I have my eyes checked?

Adults with no symptoms are generally advised to have a full eye examination every two years. If you have diabetes, high blood pressure or a family history of eye disease, yearly checks are usually recommended instead.
Can a stroke cause vision loss?

Yes, a stroke or mini-stroke (transient ischaemic attack) affecting the visual pathway in your brain can cause sudden vision loss, sometimes affecting only part of your visual field. Vision loss in one eye alongside other stroke symptoms should always be treated as a medical emergency.
What is age-related macular degeneration?

Age-related macular degeneration is a condition affecting central vision that becomes more common with age, and it can sometimes cause sudden vision loss if there is bleeding into the retina. One form, known as wet macular degeneration, can be treated with anti-VEGF injections into the eye.