If your vision becomes less clear or sharp, you have blurred vision. Some people rub their eyes to try and see better or check their glasses aren’t foggy. Many common eye problems can cause blurred vision, though it may also be a sign of a serious issue.
Blurry vision usually matches one of the following:
- Gradually your vision blurs
- Overall and sudden
- Peripheral only
- Central only
- In one eye
How blurred vision appears, where it appears, and additional symptoms will depend on the cause. You may have painful or red eyes and struggle to focus on objects. Some people with blurry vision experience dizziness, sensitivity to light and headaches.
When is blurred vision an emergency?
Sudden blurry vision accompanied by dizziness, weak or numb arms, and face dropping are signs of a stroke. Other symptoms include loss of balance and coordination, slurred speech, eye twitching, and an instant, severe headache. If you experience the above, seek emergency care immediately.
Similarly, short-term symptoms of the above may be due to a transient ischemic attack (TIA). It can serve as a stroke warning and usually lasts a few minutes only.
Blurry vision after a head injury can indicate a concussion, which sometimes requires emergency help. You may feel sick, confused or dizzy and have a headache, monitor these symptoms. Visit your doctor the next day if you experience these symptoms after a head injury. If your symptoms worsen, seek emergency assistance.
First, we will look at your overall eye health and ask questions about your symptoms. We need to know how long you have had blurry vision and if you’ve had other symptoms. Let us know if you have an underlying health condition and the medications you are taking for this. We will then determine which tests you need to diagnose the cause of blurred vision.
Tests we may perform include
- Physical examination
- Slit lamp examination
- An eye chart/ refraction test
- Tonometry (eye pressure test)
- Retinal assessment/ Ophthalmoscopy
You may also need a blood test if you are showing signs of an infection.
Short-term blurry vision
You may only experience blurred vision occasionally and for a short time. There are several possible causes for temporary blurry vision. Some may be due to looking at a screen, such as your computer or phone, too long. Other causes are related to the inner workings of your eyes. You might also have a foreign object in your eye.
Blurred vision is a symptom of ocular migraines, also known as retinal migraines. These differ from headache-type and aura migraines, though ocular migraines can also cause headaches. You might lose vision for a short time in one eye and see flashes of light.
As you age, the vitreous in your eye starts to liquefy, leading to floaters. As a floater passes around your eye, you may experience blurred vision. This usually occurs quickly. A floater can appear as a dark spot or squiggly line across your field of vision.
Pregnancy can cause blurred vision because of your body’s hormonal changes. Your eyesight should return to normal a few weeks after delivery. But, if your vision changes suddenly, speak to your doctor, as this can be a sign of pre-eclampsia.
Long-term causes and treatments
If blurred vision persists for a couple of weeks, it may be a symptom of an eye condition. Once we have determined the cause of your blurred vision, we can suggest how to counter it.
Long-term causes of blurry vision include
We explain some of these in detail below.
Anyone can experience a refractive error. Refractive errors are one of the most common causes of blurry vision, often treated with glasses or contact lenses. If you have a refractive error, you may experience blurry vision over your entire field of vision, eye strain, or glare.
You might also struggle to focus in your day-to-day life or on things nearby (long-sightedness) or far away objects (short-sightedness). If you aren’t happy with temporary measures, you want laser eye surgery to treat refractive errors.
Cataracts often cause blurred vision that worsens as the cataract does. You may find that it affects your central vision first. Other symptoms you may experience include cloudy, dim, or double vision.
Cataracts usually start forming in people after the age of 50, with noticeable symptoms, such as difficulty reading, from 60. We can address some vision impairments caused by cataracts with glasses or contact lenses. But, you will need cataract surgery to treat the cataract itself.
Glaucoma causes gradual blurriness in central vision as well as vision loss. Similar to cataracts, the symptoms become more apparent towards the later stages. You may see rainbow-coloured circles (halos) around bright lights and experience headaches. In severe cases of glaucoma, you might have intense eye pain and feel sick.
You are more likely to experience glaucoma if you are over 40 and have a family history. People with diabetes are also more likely to get glaucoma due to diabetic retinopathy. Diabetic retinopathy causes retinal blood vessels to weaken.
Glaucoma treatments aim to reduce intraocular eye pressure. These include eye drops, laser treatments, lens replacement surgery, and glaucoma surgery. Alongside treatment, some lifestyle modifications can lower your eye pressure further. We discuss this in detail in our blog: Can glaucoma be managed with lifestyle changes?
Can I prevent blurry vision?
You can often prevent temporary blurry vision with lifestyle changes, such as taking regular breaks from the computer. If you’re outside a lot, you should be wearing sunglasses. Avoid touching your eyes where possible, but wash your hands first if you need to, e.g. before inserting contacts.
You cannot prevent many eye conditions. But, we recommend following a healthy diet and exercising to maintain good eye health. Read our blog to learn more: Top 14 foods to eat for healthy eyesight. Attend an eye exam at least every two years to identify issues early.