Impaired or loss of vision

What is impaired vision?

Impaired vision means your sight can't be fully corrected with glasses or contact lenses, making everyday tasks such as reading or recognising faces harder. It ranges from mild sight loss through to blindness and can affect one or both eyes.

Symptoms of impaired vision

Vision loss can develop gradually or come on suddenly and it's more common as you get older. Symptoms can include:

• changes to your vision, or blurred or cloudy vision
• difficulty reading, watching TV or seeing people's faces clearly
• sensitivity to light or eyes that feel uncomfortable in bright light
• double vision, flashes of light, floaters or other disturbances in your vision
• difficulty seeing at night or in low light

Causes of impaired vision and who is at risk

There are many possible causes of vision loss. Worldwide, the most common are uncorrected refractive errors, such as short or long-sightedness, and cataracts, though the causes vary between countries and age groups.

In UK adults, common causes of sight loss include:

• age-related macular degeneration, the leading cause of vision loss in UK adults, where the central part of the retina wears out with age
• glaucoma, where the optic nerve is damaged, often because of increased pressure inside the eye
• cataracts, where the lens of the eye becomes cloudy
• diabetic retinopathy, a complication of diabetes that damages blood vessels in the retina
• uncorrected refractive errors, where the shape of your eye stops light focusing correctly
• corneal opacity or trachoma, which scar or cloud the cornea
• hemianopia, a loss of half the field of vision that can follow a stroke.

You're more likely to experience vision loss as you get older; most people with significant sight loss worldwide are over 50.

Are there different types of impaired vision?

Classification of sight loss is based on how well you see detail (visual acuity) and how much you can see to the side when looking ahead (visual field). The 2 main categories are:

• sight impaired, previously called partially sighted
• severely sight impaired, previously called blind

How impaired vision is diagnosed

If you're worried about your sight, book an appointment with an optician for a check-up. They'll refer you to an eye specialist, called an ophthalmologist, if you need further tests.

To assess whether you're eligible for certification, an ophthalmologist tests your visual acuity and visual field in both eyes. If you meet the criteria, they'll complete a Certificate of Vision Impairment, which is sent to you, your GP and your local social services team.

How impaired vision is treated

Treatment depends entirely on what's causing your vision loss. If your optician or GP thinks a treatable condition is behind your symptoms, you'll usually be referred to an ophthalmologist for further tests, and treatment may include medicines or surgery to improve your vision or stop it getting worse.

Some conditions cause permanent vision loss that can't be treated. If this applies to you, support can include:

• low vision aids and assistive technology, for tasks such as reading, using a phone, or using the internet
• advice on adapting your home, for things like cooking and washing
• help with travelling and using transport
• advice on benefits, since being certified as sight impaired or severely sight impaired can help you access financial and practical support
• support with learning, work, or workplace adaptations
• talking therapies, such as cognitive behavioural therapy (CBT) or counselling.

Registering as sight impaired is voluntary and confidential. It means being added to your local council's register of blind and partially sighted people, and it can help you access low vision services, benefits and concessions, such as a reduced TV licence fee or help with NHS costs.

When to see a doctor

See an optician if you think you may have vision loss; early diagnosis and treatment may help stop it getting worse.

Get an urgent GP or optician's appointment or contact NHS 111 if you have:

• changes in vision, such as blurred vision, double vision, or flashing lights or shapes
• a dark shadow moving across your vision
• pain in one or both eyes
• a red, painful eye, or eyes that feel uncomfortable in bright light.

Go to A&E or call 999 immediately if you suddenly can't see from one or both eyes, or you suddenly have severe eye pain. Don't drive yourself there; ask someone to drive you or call 999 for an ambulance.