Sudden Blurry Vision In Both Eyes: Causes & When To Get Help

You’re going about your day when your surroundings turn slightly fuzzy out of nowhere, like someone has drawn a soft curtain over your eyes. Sudden blurry vision in both eyes can feel confusing, unsettling, and even a little scary. While it’s sometimes caused by something simple like fatigue, other times it can signal something more serious, possibly even a medical emergency that needs urgent care.

So how do you know when it’s harmless and when it’s time to take action?

In this article, we’ll discuss possible causes, key symptoms to watch for, and when to seek help. Our goal is to help you better understand your symptoms so you can confidently protect your eye health.

Understanding Blurry Vision

Have you noticed your surroundings suddenly lose their crispness, like you’re viewing the world through fogged-up glasses? That sensation, known as blurry vision, often signals that something in your visual system isn’t working quite as it should.

When both eyes are affected at the same time, particularly if the change happens suddenly, it may raise more concern than if it’s isolated to just one eye.

That’s because blurriness in both eyes can sometimes point to broader, systemic issues involving your blood flow, optic nerve, or even the visual processing areas of your brain.

While not every episode of blurry vision is urgent, listening to your body is important. Vision is one of our most relied-upon senses, and even small changes can be your eyes’ way of asking for help.

Knowing what to look out for, and what not to ignore, can make all the difference when it comes to preserving your eye health and quality of life.

Common Causes Of Sudden Blurry Vision In Both Eyes

If your vision has changed suddenly, and in both eyes, it’s not something to dismiss. Although there are many potential causes of blurred or hazy eyesight, some may require urgent care to prevent permanent damage.

Let’s explore the most likely reasons you might experience sudden blurry vision in both eyes, especially when the change feels unexplained or comes on quickly.

1. Systemic Circulatory Issues

Your eyes rely on a steady, healthy supply of blood to function properly. Sudden spikes or drops in blood pressure or blood sugar can interfere with this balance, affecting both eyes at once.

High Blood Pressure

Elevated blood pressure may damage the tiny blood vessels in the retina. You might notice sudden blurred vision, dark spots, or reduced sharpness. Headaches or chest discomfort may accompany these changes.

High Blood Sugar

In people with diabetes, high blood sugar can cause the lens of the eye to swell, distorting vision in both eyes. Over time, this may also contribute to diabetic retinopathy, where blood vessels in the retina leak or bleed.

Warning signs include:

• Blurry vision that fluctuates
• Difficulty focusing
• Blind spots or floaters
• Trouble with night vision

Even if your symptoms seem to come and go, don’t brush them off. This could be your body’s way of asking for help.

2. Optic Neuritis

When the optic nerve becomes inflamed, it disrupts the flow of visual information between your eyes and brain. This condition often develops rapidly, and in some cases, both eyes can be affected.

You may experience:

• Foggy or dimmed vision
• Eye pain, especially when moving your eyes
• Washed-out or dull colours
• Loss of central vision or blind spots

Optic neuritis is often linked to autoimmune or neurological conditions. To reduce the risk of lasting effects, it requires prompt and appropriate treatment.

3. Transient Ischaemic Attack (TIA) Or Stroke

In some cases, sudden blurry vision in both eyes may be a neurological emergency, a sign that blood flow to the brain has been disrupted.

This can happen during a TIA (mini-stroke) or a full stroke, particularly if it affects the visual processing areas of your brain.

Seek immediate care if you experience:

• Sudden loss of vision in both eyes
• Double vision
• Weakness or numbness
• Slurred speech or confusion
• Loss of balance

Early intervention can protect not just your vision, but your overall health and well-being.

4. Visual Migraines (With Or Without Headache)

Visual migraines, or retinal migraines with aura, can temporarily affect your vision in both eyes. These episodes may occur with or without a headache, which can make them tricky to recognise at first.

Common visual symptoms include:

• Wavy lines, zigzag patterns
• Flashing lights
• A temporary blind spot in the centre or edge of your vision
• Light sensitivity

The visual disturbances usually last less than an hour but can feel unsettling while they’re happening. If your symptoms change over time, or appear without warning, a check-up with your eye doctor is always wise.

5. Brain Tumours Or Neurological Disorders

Vision changes in both eyes, especially when accompanied by balance issues, headaches, or changes in peripheral vision, can sometimes be linked to brain disorders.

These symptoms may suggest pressure on areas of the brain responsible for visual processing, such as the occipital lobe or optic pathways.

While rare, conditions such as brain tumours, multiple sclerosis, or traumatic brain injuries may cause:

• Blurred or distorted vision in both eyes
• Difficulty tracking movement
• Changes in visual field
• Ongoing light sensitivity or eye discomfort

Diagnosis may require imaging and neurological evaluation, but early intervention makes a real difference.

6. Severe Inflammation Or Infection (Affecting Both Eyes)

Infections like uveitis or systemic inflammatory conditions can affect the entire visual system, not just one eye. These may cause:

• Sudden, painful blurred vision
• Redness, light sensitivity, or discharge
• A general feeling of eye pressure or discomfort
• In rare cases, temporary blindness

Unlike typical eye infections, these are not always contagious. They may be linked to autoimmune disorders or systemic illness, and often require advanced care.

7. Angle-Closure Glaucoma (Bilateral Cases)

While glaucoma is commonly thought of as a gradual, one-sided condition, there are cases, particularly with angle-closure glaucoma, where both eyes can be affected quickly.

This type of glaucoma may cause:

• Sudden severe eye pain
• Blurry eyesight in both eyes
• Nausea and vomiting
• Halos around lights

This is a serious medical emergency. If these symptoms appear suddenly, immediate treatment may help preserve your vision.

8. Side Effects Of Medications Or Treatments

Certain medications, especially those used for autoimmune conditions, chemotherapy, or high blood pressure, may affect your visual field or clarity in both eyes.

If you’ve recently started a new medication and notice any of the following, contact your prescribing doctor:

• Hazy or blurry vision
• Difficulty focusing
• Uncomfortable light sensitivity
• Headaches linked to screen or light exposure

It’s important not to stop taking any prescribed treatment without first consulting a healthcare professional.

9. Macular Degeneration (Rapid Progression In Both Eyes)

You may be familiar with macular degeneration as a condition that typically affects one eye at a time, but in some cases, particularly with wet macular degeneration, changes can happen quickly and bilaterally.

Look out for:

• Wavy lines in your central vision
• Trouble reading or recognising faces
• Dark or blind spots that develop suddenly
• Blurry vision in both eyes that doesn’t go away

Early detection gives you more treatment options, and a better chance of preserving your central vision.

10. Environmental Or Lifestyle Factors (Triggering Both Eyes)

Don’t overlook the impact of daily habits. Certain environmental factors or lifestyle triggers can lead to sudden changes in vision, such as:

• Prolonged screen time
• Exposure to strong wind, smoke, or allergens
• Poor sleep
• Intense physical exertion

These usually cause transient blurriness, but it’s important to rule out any underlying cause if your symptoms persist or worsen.

Noticing Blurry Vision In One Eye Instead?

If you’re only experiencing symptoms in one eye, it’s worth exploring more eye-specific causes, like refractive errors, cataracts, or retinal detachment, in our dedicated article on blurry vision in one eye. That resource goes deeper into single-eye symptoms and how they’re commonly managed.

When To Seek Help

Noticing a sudden shift in how clearly you see, especially in both eyes, can feel unsettling. It might be tempting to wait it out and hope it clears up, but acting early can make a meaningful difference to your eye health.

While some visual changes are minor or short-lived, others may signal more serious underlying issues. And the tricky part? It’s not always easy to tell which is which. That’s why getting a professional opinion can give you peace of mind, and in some cases, help protect your long-term vision.

You should get in touch with your eye doctor if you notice:

• New floaters, flashes of light, or shadowy spots in your vision
• A sensation of pressure, discomfort, or pain in or around your eyes
• Difficulty recognising familiar faces, reading, or focusing clearly
• A sudden unexplained change in how you see, even without pain

If something doesn’t feel quite right, trust your instincts. Early assessment often leads to the best outcomes, whether it’s reassurance or timely treatment. Your vision is worth protecting, and support is just a call away.

Frequently Asked Questions

Can dry eyes cause blurred vision?

Yes, eye strain and dry eyes can cause temporary blurred vision, especially after long screen use or exposure to wind and dry air.

Is blurry vision after waking up normal?

Some people notice blurry vision when they first wake up due to dry eyes, sleep position, or residue from eye creams. It usually clears within a few minutes. However, if the blurriness lingers or worsens, it’s worth looking at it.

Can anxiety or stress make your vision blurry?

It’s possible. High stress or anxiety levels may trigger physical changes in the body, like muscle tension, dry eyes, or disrupted blood flow that can temporarily affect how clearly you see.

While this type of vision change is often short-lived, it’s still wise to have any sudden or unusual blurriness assessed by an eye care professional to rule out other potential causes.

Will blurry vision in both eyes go away on its own?

That depends on what’s causing it. Some cases, like fatigue or eye strain, may resolve independently, while others may require treatment to prevent long-term vision issues. If you’re unsure, booking a professional assessment is better than waiting and seeing.

Can dehydration cause blurry vision?

Yes, dehydration can lead to dry eyes and reduce tear production, which may cause temporary blurry vision.

However, if you’re experiencing other symptoms or the blurriness suddenly affects both eyes, it’s best not to assume dehydration is the only cause; consider speaking to a healthcare provider.

What should I do if my blurry vision keeps coming and going?

If your vision changes frequently, especially in both eyes, it’s important to have it assessed.

Fluctuating vision can be linked to underlying health conditions like diabetes, migraines, or circulatory issues. An eye exam can help determine whether further testing is needed.

Conclusion

Experiencing sudden blurry vision in both eyes can be unsettling, but it’s also your body’s way of telling you something may need attention. Early recognition and care are key from manageable conditions like dry eyes to more urgent causes like stroke or retinal detachment.

If your vision has changed suddenly or feels different in any way, don’t wait. Trust your instincts and schedule a comprehensive eye examination. Your eyesight is precious, and with the right care and prompt treatment, you can protect and maintain clear vision for years to come.

If your vision suddenly becomes blurry in both eyes, even if it seems mild or disappears, your eyes may be telling you something important. The sooner you seek guidance, the better your chances of protecting your sight.

Contact Mornington Peninsula Eye Clinic today at (03) 9070 3580 to book an eye health consultation. We’re here to help you see clearly and confidently.

Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.

References

Blurred Vision [Internet]. Healthdirect. 2023 [cited 2025 Jul 23]. Available from: https://www.healthdirect.gov.au/blurred-vision

Gardner A. 8 Causes of Blurry Vision—and When To Seek Care [Internet]. Health. 2025 [cited 2025 Jul 23]. Available from: https://www.health.com/condition/eye-health/blurry-vision-causes

Bedinghaus T. Blurry Vision and Headache: Causes and Signs of an Emergency [Internet]. Verywell Health. 2025 [cited 2025 Jul 23]. Available from: https://www.verywellhealth.com/vision-and-headache-3422017

Sissons B. What to Know About Dehydration and the Eyes [Internet]. Medical News Today. 2023 [cited 2025 Jul 23]. Available from: https://www.medicalnewstoday.com/articles/can-dehydration-affect-your-eyes