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Gradual or sudden vision changes: Is this normal?

stop sign that is blurry

Fluctuating vision — when the sharpness (or acuity) of your eyesight changes frequently —  can be caused by one of a number of temporary conditions or developing, potentially long-term health problems.

When someone experiences vision fluctuations, they can happen on a weekly, daily or even hourly basis. But there isn’t always a pattern to how long these vision changes last.

What causes vision to fluctuate?

Many issues and conditions can lead to blurry vision that comes and goes. Some issues will go away with time, while other conditions will need to be monitored and/or treated by an eye doctor or specialist. More common culprits include:

  • Eye strain

  • Dry eyes

  • Poor sleep habits

  • Diabetes

  • Cataracts

  • Certain medications

Eye strain

Electronic screen use has been on an exponential rise for years, and digital eye strain can be an unwelcome side effect. The words and images on digital screens are a little harder for your eyes to focus on, so the tiny muscles inside the eye can get tired more quickly than they would if you were reading a book or newspaper.

Blurry, fluctuating vision is one of the most common complaints among people who use digital screens for extended periods throughout the day. The clarity of your vision can seem to come and go as the hours go by. This is a temporary vision fluctuation, and your eyesight should go back to normal during your next screen break.

An easy way to relax your eye muscles throughout the day is to practice the 20-20-20 rule: For every 20 minutes of digital screen use, look at an object about 20 feet away for at least 20 seconds.

Dry Eyes

Digital eye strain can also lead to dry eye syndrome, but dry eyes can occur for other reasons as well.

When your eyes don’t produce enough lubrication, your vision can become blurry now and then. This can happen as the result of poor tear production, oil gland blockages (blepharitis) or simply not blinking enough. People tend to blink less frequently when they use digital screens, and fewer blinks means less lubrication spread across the surface of the eye.

SEE RELATED: Blinking frequency

Poor sleep habits

A poor sleep schedule can wreak havoc on the human body, and the eyes are no exception. Too often, insomnia leads to increased stress throughout the day, creating a cycle that’s difficult to break.

In addition to the neurological effects of sleep deprivation and the stress that comes with it, not getting enough sleep can reduce the amount of tears you produce. This dryness can cause mildly blurred vision that seems to come and go.

Certain medications

Some medications can have an effect on your vision, and some can even cause temporary blurred vision. Check with your doctor or pharmacist to make sure vision fluctuations aren’t a side effect of the drug you’ve been prescribed and, if so, whether they can recommend an alternative medication.


Diabetes can cause blood sugar levels to get too high or too low, especially when the disease isn’t being properly managed. High blood glucose (hyperglycemia) and low blood glucose (hypoglycemia) can both affect your vision.

During hyperglycemia, water gets pulled into the eye’s lens. When water causes the lens to expand, it warps the light that passes through it and makes everything look blurry.

Hypoglycemia, on the other hand, does not affect the eye directly. Instead, it affects the brain and the way it perceives visual objects.

It can take several weeks for diabetes-related vision fluctuations to go away, since the symptom is directly tied to the current blood sugar level. However, blurry vision will return the next time blood glucose spikes or dips. If you have diabetes, talk to your doctor if you experience vision changes.

SEE RELATED: Blurry vision with diabetes

These aren’t the only factors that can lead to fluctuating vision. In addition to others, the following situations and conditions can also cause occasional blurry vision:

  • LASIK surgery: Mild vision fluctuation after surgery is normal, but speak with your surgeon if blurry vision worsens or doesn’t go away.

  • Pregnancy: Certain hormonal changes can cause the eyes’ corneas to change shape, sometimes resulting in temporary blurred vision during pregnancy.

  • Migraines: Intense headaches can cause temporary light sensitivity, blurry vision and other visual disturbances, sometimes only in one eye. Less often, migraines can also occur without typical migraine symptoms like pain and nausea.

  • Vertigo: This condition can cause dizziness, disorientation, loss of balance and mild visual fluctuations.

  • Macular degeneration: AMD is a degenerative disease that leads to a loss of central vision over time. It can lead to reduced vision and blurry vision that comes and goes.

  • Stroke: In some cases, a stroke will cause fluctuating vision, along with other neurological symptoms. If you experience any of the warning signs of stroke, seek immediate medical care.

When to see an eye doctor

Fluctuating blurry vision can be harmless, but it can also be a symptom of an underlying disorder. If your vision fluctuations become more common or start to get worse, schedule an exam with an eye doctor.

An eye doctor can use special instruments to look inside your eye and rule out any serious eye conditions. If necessary, they will be able to refer you to a specialist for further care.

READ MORE: Can COVID-19 cause blurred vision?

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