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When should you worry about your eyes?

When should you worry about your eyes?

Most people will have had their eyes tested at some point to check for problems with vision and eye health. The NHS recommends those with no obvious symptoms get this sort of test at least every two years to ensure eyes remain healthy and any emerging problems are picked up. But if you start to notice changes in your vision, or other problems with your eyes, it may be necessary to see an eye specialist more urgently.

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Finding it harder to read

Even if you haven't needed glasses in the past, many people aged 40 and over may start to require a prescription for reading glasses. This is known as presbyopia and is a normal change in the eyes' ability to focus at different distances. If you begin to gradually notice problems with reading texts up close, or find you have to hold certain items - such as a restaurant menu - further away to see them properly, it may be a sign of this natural alteration.

If you notice these sorts of changes, it's important to make an appointment with your optician, who will be able to rule out any other causes and prescribe you appropriate glasses or contact lenses.

Blurred vision

If your vision becomes blurry, it can be alarming. But although it's important to get checked out quickly to rule out more serious problems, it may be caused by something innocuous. "If your vision is blurry, you need to ask yourself the following questions," says Robert Longhurst Consultant Optometrist at Phoenix Hospital, Harley Street. "Are my eyes suddenly blurry or has it been a gradual process? Are my eyes always blurry or just sometimes? Is it one eye that is blurry or both of my eyes?

"Vision that is blurry just sometimes and that clears after blinking is quite often a dry eye. A gradual blurring of vision that cannot be corrected with glasses is sometimes caused by developing cataracts," he explains.

"However, if somebody has a sudden blurring of their vision, this is more likely to be something serious, such as a detached retina or a stroke. Both require urgent medical attention, even if the vision comes back after a while," he advises.

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Sudden loss of vision

If you lose your vision entirely, even if it comes back after a short period of time, it’s important to seek urgent medical advice. "Amaurosis fugax is a temporary loss of vision in one or both eyes due to a lack of blood flow to the retina. This needs urgent investigation as it could be a precursor to a stroke," explains Longhurst. As this could be a symptom of a serious condition, it's important to seek emergency care.

Visual disturbance

Some people also experience visual disturbances, which range from "seeing straight lines as being wavy" or "zig-zags or shimmering light". Others may even experience "visual hallucinations, such as seeing people you know aren't there, which is surprisingly common," says Longhurst.

"The most common visual disturbance is probably floaters, which are the little black spots or cobwebs you get in your vision that drift about as you move your eyes. Most of the time, floaters are caused by changes in the jelly inside the eye as we get older. We all tend to notice floaters from time to time and they are usually nothing to worry about.

"However, if you have a sudden increase in floaters, you should see your optician, especially if you have flashing lights too, as this may indicate a posterior vitreous detachment. This is where the jelly changes where the retina is. For most people, this is harmless, but occasionally the retina will tear, which is why it is important to be seen. A retinal tear can lead to a detachment and sight loss.

"Anyone concerned about any visual disturbance should see their optician, and anyone with flashing lights and floaters needs to be seen urgently to make sure they do not have a tear," advises Longhurst.

Patient picks for Other eye problems

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Red eyes

It's not uncommon for people to experience a reddening of one or both of the eyes, and there can be a number of different causes from irritation to infection.

Hay fever

During spring and summer months, many people suffer from hay fever, which can cause eye irritation and redness. If you have hay fever and experience this symptom, you may find eye drops containing antihistamine help to reduce redness and itching.


Allergic or infective conjunctivitis is one of the most common causes of red or pink eye. "This is a common eye inflammation usually caused by an irritant or a bacterium or virus," explains Longhurst.

This condition is often infectious, so you may need to take time off work or study. If you experience symptoms alongside the redness that include itching, watery eyes, or pus, it's likely that conjunctivitis is the cause. This condition can often be treated at home, using sterile (boiled and cooled) water and cotton wool to clean the eye area.

However, it may require additional medication. Your pharmacist can provide the same medication you would get on prescription from a GP, and can also confirm if any further action is needed.


Blepharitis presents in a similar way to conjunctivitis, but is an inflammation of the margins or edges of the eyelid. It can be accompanied by the redness and itching of conjunctivitis, as well as flakes and crusting around the eyelid area. Some patients complain that their eyelids are stuck together in the morning. This condition can usually be treated by regular 'lid hygiene' - outlined in more detail in our leaflet - but can take a considerable time to settle.

Subconjunctival haemorrhage

Despite the alarming name, this cause of a sudden-onset painless red eye is not serious, and is more like a bruise on the eye. "This type of bruise can be caused by injury, or even a cough or sneeze," explains Longhurst. "Rarely, it may also be a symptom of high blood pressure."

Other causes

If you experience red eye that is accompanied by light sensitivity, it may be a condition called uveitis, which is an inflammation of the middle layer of the eye. It's important to seek medical advice for this combination of symptoms as it may be necessary to treat with steroids.

Contact lens wearers

In addition, if you are a contact lens wearer, this can make you more susceptible to certain infections. If you experience any of the above symptoms, remove your contact lens and speak to your optician or pharmacist.

"Although for the most part, a red eye does not have a sinister cause, anyone with red eye should get it looked at," advises Longhurst. "Opticians are trained to diagnose most causes of a red eye and some can even prescribe medication." If you are unable to see an optician, ask your pharmacist for advice.

Eye pain

Eye soreness or pain can be a worrying symptom, but is not necessarily an indicator of something serious unless teamed with other symptoms. Nevertheless if you suffer from eye pain, it's important to see your optician. If the pain is severe and accompanied by visual changes, it's time for an immediate trip to A&E.

"Eye pain without any other symptoms, such as a red eye, is rarely serious. And I see a lot of patients with eye pain that feels as though the pain is coming from behind their eye, which is actually because of an issue with their cornea at the front of the eye. Quite often this is just dry eye or a foreign body," explains Longhurst.

"However, eye pain can signify something more serious, especially if it is accompanied by a red eye or sensitivity to light. For example, eye inflammation can cause your eye to be painful and depending on where the inflammation is, this could be sight-threatening. My advice to anyone with eye pain would be to call their optician for advice," says Longhurst.

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The information on this page is peer reviewed by qualified clinicians.

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