Blurry vision

Medically reviewed by Sharon Copeland on 11 March 2021

What is blurry vision?

Blurry vision makes objects appear hazy or out of focus, it stops people from being able to see fine detail. It mostly affects both eyes, but some people also experience it in only one eye.

Blurry vision can last for just a few moments, or far longer depending on the cause. In some cases, it can be permanent.

Cloudy vision can often be mistaken for blurry vision; however, it is usually a symptom of a specific condition such as cataracts. However, they both cause objects to appear obscured.

What causes blurry vision?

The leading causes of blurred vision are refractive errors – myopia (short-sightedness) hyperopia (long-sightedness), astigmatism and presbyopia. Blurry vision can also be a sign of an eye disease/ more serious, underlying issues. For this reason, you should see an eye care specialist should blurry vision persist.

Wearing contact lenses for too long can cause proteins and other debris in your tear film to accumulate and contribute to the hazy vision. That's why you should wear your contacts as recommended by the manufacturer and your optician. Not cleaning your lenses properly can also cause blurred vision.

High blood pressure can damage the vessels supplying blood to your retina, causing retinopathy, a condition that can lead to bleeding in the eye, blurred vision and complete loss of sight.

Other causes of blurred vision include ocular migraines or migraine headaches, eye floaters, certain medications such as allergy medication and eye conditions such as cataracts, glaucoma and age-related macular degeneration.

Why has my vision suddenly gone blurry?

If your vision has gone blurry suddenly, this could be part of the warning signs of a severe eye problem or health condition. Health conditions can include the following:

• A stroke-this can affect the retina and is known as retinal vessel occlusion. It is caused by a blockage in a retinal vein and can lead to blurry vision.
• Preeclampsia-this usually consists of high blood pressure and protein in your urine. It more commonly occurs in late pregnancy and can be life-threatening to you and your baby. While symptoms may not always appear, blurry vision and seeing flashing lights can be an indicator of the condition.
• Brain Tumour-the build-up of pressure in the skull as a result of a brain tumour can lead to blurry vision.
• Multiple Sclerosis-this disease can cause inflammation of the optic nerve, causing optic neuritis, which can lead to various vision problems, including blurry vision.
• Diabetes-this can lead to diabetic retinopathy which causes blurry vision and affects your eye health. This condition arises when the blood vessels of the retina are damaged.
• Glaucoma-the first sign of glaucoma is total blurred vision. Blurred vision from glaucoma happens when the optic nerve gets damaged due to too much pressure on the eyeball.
• Migraines-blurry vision often accompanies a migraine and is also known as aura.
• Hyperthermia-this is when the body temperature becomes exceptionally high. Abnormally high temperature causes the brain to work harder than usual in the body's attempt to sweat and get rid of the heat. When the brain works harder to do this, the functionality of other parts of the body reduces, causing blurry vision and vision loss.

Is sudden blurry vision an emergency?

Mild blurry vision could be a sign of eyestrain or fatigue. A sudden blurry vision should be treated as an emergency as it could be a symptom of any of the conditions above.

There are very few ways of recovering complete vision loss. So, whether you experience blurred vision, double vision, blind spots, seeing halos around lights, or a dimness, you should seek advice from your doctor immediately.

How do you get rid of blurry vision?

Treatment for blurry vision depends on the cause. An optometrist will be able to diagnose the root of the problem with an eye examination and recommend an appropriate treatment. Your exam will usually consist of a Snellen eye chart test, slit lamp and measurement of spatial contrast sensitivity.

If you're short or long-sighted, treatment most commonly consists of corrective lenses. Another more invasive option is LASIK eye surgery. With this option, you may encounter temporary blurry vision after surgery, but this will hopefully clear up after a few days.

Multifocal contact lenses can also correct presbyopia. Those with astigmatism will be prescribed toric lenses.

Blurred vision, when temporary, can be caused by high blood sugar levels. High blood sugar levels can cause the lens of your eye to swell, which then affects your sight. To correct your vision, getting your blood sugar levels back to a healthy range is vital.

Depending on what’s causing the blurred vision, other treatments include eye drops and medications.

How is blurry vision prevented?

It's not always possible to prevent blurry vision; however, specific eye care measures can prevent blurry vision caused by lifestyle-related factors. Here are some tips to look after your eyes and avoid blurry vision as best as possible:

• Wear sunglasses with 100% UV protection
• Don't smoke
• Visit your optician for regular eye tests
• Follow a hygienic contact lens care routine
• Follow a healthy diet, rich in antioxidants, omega-3 fatty acids and vitamin A

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