Blurry vision is not a condition itself, it’s more a symptom of other eye conditions or simply a sign that you may need new or updated glasses or contact lenses. Here we take a look at some of the more common causes of sudden and ongoing blurred vision and what you can do to tackle these symptoms.

Why is my vision blurry?

Whether your vision is blurred in one or both eyes, temporarily, suddenly or a gradual build-up, we know that anything that impairs your vision can be concerning. 

Let’s take a look at some of the more common scenarios we hear about when people complain of blurred vision.

What causes blurry vision and headaches together?

The most common cause for a headache and blurred vision is usually to do with uncorrected vision problems linked to needing new or updated glasses or contact lenses.

Even if you have ‘perfect vision’, some blur and eye strain is normal when our eyes are tired or strained, this can often feel like pain in the frontal brow or headache. This is often called asthenopia and could have many underlying causes from general over concentration, loss of focus in the eye due to presbyopia or other issues such as eye muscle problems.

Another cause could be migraine. People who suffer from migraines report temporary vision loss or blurred vision as a result of distorted lines or colours, sometimes in one eye, sometimes in both. Ocular migraines don’t always have accompanying head pain or headache like a normal migraine.

Whatever the cause, consulting your optometrist is the right thing to do when these symptoms present.

Other causes for blurred vision and headache could include:

Low blood sugar: if your blood sugar gets too low, you can become hypoglycaemic, which means your brain is in desperate need of glucose to keep it going.

Stroke: aside from other symptoms like facial and arm weakness and slurred speech, a stroke can cause a headache and blurred vision. If you suspect a stroke act quickly to seek medical help.

Head trauma: if you’ve bumped your head, be on the lookout for concussion in the hours, days or even weeks afterwards – the symptoms of which can be a headache and blurry vision.

Carbon monoxide poisoning: when you burn fuel, you produce carbon monoxide which is dangerous if breathed it. Unfortunately, it’s hard to detect carbon monoxide because it doesn’t smell of anything. A common sign that you have carbon monoxide poisoning is a headache and blurry vision.

Why do I experience blurry vision in the morning when I wake up?

For the most part, blurry vision when you wake up is caused by dried or lack of tears on the front of your eye, it usually clears when you blink a few times as the natural debris is removed, and the tear film refreshes.

Your eyes can dry up as the result of being dehydrated (see also feeling hungover), allergies, sleeping with a fan on, leaving your contact lenses in (when they’re not designed for overnight wear) and even some medications.

Diabetics may wake up with blurry vision as a result of their blood sugar levels altering overnight – this may also be linked with feeling dizzy.

Why is my peripheral vision blurry?

It can be quite difficult to spot that your peripheral vision (the area around the outside of you field of sight) is blurry, which is why it is so important to have regular eye tests so we can spot if there’s a problem early.

You might start to notice there’s a problem when you trip over objects out of your central field of view, find driving at night tricky or struggle to see in low light. 

One of the main causes of peripheral vision loss is glaucoma. Unlike acute glaucoma, which can cause sudden blurry vision as a result of pressure build up in the eye, chronic glaucoma is much slower to develop and, as such, is harder to detect without professional help. If you have any issues with your peripheral vision book an eye test as soon as possible.

Another condition affecting peripheral vision to be aware of is retinitis pigmentosa, which is usually a result of genetic disorders that affect the retina causing the cells to alter and not work as well.

What’s the difference between blurry and cloudy vision?

Unlike blurry vision, where objects are out of focus or distorted, cloudy vision is like looking through foggy window. It can make colours seem muted and give you halos around lights. Cloudy vision may be accompanied by blurred vision and is often the result of cataracts. 

Eye conditions that can cause blurred vision

Blurry vision is a common symptom when it comes to eye conditions – here we take a look at some of the more common causes:

Refractive error

This is basically a change in how well you can see, whether it’s down to being long-sighted, short-sighted, have an astigmatism or presbyopia. This means your vision might be blurred at a distance or close up. Thankfully glasses, varifocals or contact lenses can give you clear vision once again.

Cataract

Cataracts usually develop slowly over many years, so you may not notice symptoms at first but will eventually find that your vision is blurry or cloudy. They often develop in both eyes, although each eye may be affected differently.

Macular degeneration

Until you notice a loss of vision, you may not even know you have age-related macular degeneration. Dry AMD affects your ability to see fine detail whereas Wet AMD involves a sudden change in your central vision, usually in one eye. If your vision is blurred suddenly, usually in the centre, or if straight lines and edges appear wavy or distorted, contact an optometrist. 

Macular oedema

Often linked with diabetics, macular oedema occurs when fluid build-ups in your macula causing blurred vision, parts of the vision that seems to be missing or distorted often with muted colours. If you experience any of these symptoms contact an optometrist.

Age 40-55?

If you’re an adult aged around 40-55, it might be that you’re experiencing blurry vision as a result of presbyopia. Presbyopia is a common effect of ageing, and you may begin to experience blurry vision in everyday scenarios such as when reading at normal reading distance or looking at your phone up-close.

If this sounds like something you’re experiencing, it’s worth booking an appointment with an optician to have a closer look at your eye health.

What causes sudden blurred vision in one eye?

If you can’t see very well out of one eye, the first thing is to check if there is something in it. If there is, try blinking slowly to push it to the corner of your eye and to create tears. If you splash chemicals into or feel something penetrate your eye, seek immediate medical advice.

Other conditions to look out for are:

Blurry vision during pregnancy

Aside from sickness, achy back and all the other side effects of growing another human being, some pregnant women may experience blurred vision. This is probably due to hormonal changes that cause water retention which, in turn, can increase pressure in the eye. Progesterone can also cause the cornea to soften which creates blurred or double vision.

Mums-to-be at risk of preeclampsia or gestational diabetes should also chat to their midwife if they notice any changes in their vision.

If you’re getting blurred vision while pregnant, be kind to your eyes – try to avoid wearing contact lenses, gets lots of sleep (or at least close your eyes for a bit) and ask your optometrist for any eye exercises that will help.

Blurry vision and diabetes

If you’re diabetic, you’ll need to be monitored closely for diabetic retinopathy - a complication of diabetes that damages the light-sensitive layer at the back of the eye called the retina.

There are different stages of diabetic change that affect (or don’t affect in the early stages) your vision. You can read much more about diabetic retinopathy here.

Blurry vision treatments

In the vast majority of cases, your blurry vision can be resolved with a few blinks of the eye.

For blurred vision that just won’t shift, the treatment will depend very much on the cause.

Treatment might be new or updated glasses or contact lenses, eye drops, medication or other treatment to tackle the underlying cause.

We’re always available to chat to if you need us, please don’t wait to get some help.

If you’re worried about blurred vision book an eye test or Ask the Expert. If your blurry vision is accompanied by pain, vomiting/nausea, numbness or generally not feeling right – seek emergency care.

FAQs

How long after cataract surgery is vision blurry?

Blurred vision after cataract surgery is pretty normal and may even last for a few weeks, you will usually be checked up on after your surgery by the surgical team or your community optometrist. However, if it continues after a length of time after surgery as advised by your surgeon, or if you begin to experience sudden changes, it can be a sign of something not being quite right, so it’s worth chatting to your optometrist or GP. Read more.