Blurry vision after eating can be distressing, but it’s usually temporary. Most commonly, blurry vision after eating is an early symptom of diabetes mellitus. It occurs because high blood sugar spikes can cause swelling inside the lenses of the eyes.

Repeated blurry vision after meals is a sign that you should make an appointment with a doctor. Managing your blood sugar can stop blurry vision after eating.

Diabetes affects how your body manages blood sugar. It can lead to rapid increases in your blood sugar after you finish a meal. This might not seem connected to your vision, but there’s actually a direct link.

High blood sugar levels cause fluid to move into your eyes, which can create swelling in the lenses. The swelling changes the shape of your eyes, which results in temporary blurred vision. Your vision will return to normal when your blood sugar does.

Certain foods are more likely to spike blood sugar and lead to blurred vision. Generally, these include foods very high in carbohydrates. Common examples include:

  • potatoes in any form, including french fries and hash browns
  • white flour pasta
  • white rice
  • most cereals
  • most fast food meals
  • candy bars and packaged baked goods
  • high-sugar beverages
  • fruit juice

The way you eat can also lead to spikes in your blood sugar. For instance, skipping breakfast and waiting until later in the day to eat can result in a blood sugar increase.

Properly managing your diabetes can help reduce episodes of blurred vision after eating.

Your carotid arteries are the blood vessels in your neck that bring blood to your eyes and your brain. You can feel them by locating the pulse underneath your jaw.

When these arteries can become narrowed, it’s called carotid stenosis, often brought on by carotid artery disease. Carotid stenosis and carotid artery disease can lead to serious complications including stroke.

Carotid stenosis can also cause changes to your vision. Since your carotid arteries supply blood to your eyes, a narrowing or blockage of these arteries means your eyes aren’t getting the blood oxygen they need to work correctly. You might experience blurred vision or even vision loss in one eye when you have carotid stenosis.

Vision changes after eating aren’t generally considered to be a symptom of carotid stenosis. However, there are people with carotid stenosis who have reported blurry vision after meals, so there might be a direct and immediate link for some people.

There are several other common causes for blurry vision. Some are minor and will go away on their own. Others will need medical treatment as soon as possible. Some of these other causes of blurry vision include:

  • Eye strain. Eye strain from computer work, reading, driving, and other activities can lead to temporary blurry vision.
  • Allergies. Allergies can cause your eyes to itch and burn and might lead to blurry vision.
  • Migraine. The aura before a migraine can cause blurred vision.
  • Medications. Certain medications can cause blurry vision, including antidepressants and heart medications.
  • Conjunctivitis. Conjunctivitis is also called pink eye. This common infection is spread easily and can be caused by a virus, bacteria, or allergies. It often causes itchy eyes and blurred vision.
  • Eye injury. An eye injury, such as a corneal abrasion, can happen when something scratches the surface of your eye. It can lead to blurry vision and the feeling that there is something in your eye you can’t remove.
  • Keratitis. Keratitis is a bacterial infection of your eye. Often, it’s caused by unsafe contact lens use, such as wearing the same pair of contacts for too long. You might also have eye discharge with this condition.
  • Detached retina. A detached retina is a medical emergency that happens when your retina tears away from the rest of your eye. It causes sudden flashes of lights, black spots, and an area of blurry vision. It may also cause a sudden storm of floaters or the appearance of a “curtain” coming down over your vision. It can lead to permanent vision damage or loss without treatment.
  • Angle closure glaucoma. Angle closure glaucoma occurs when your eye’s drainage system is blocked, leading to pressure, swelling, and blurred vision. Angle closure glaucoma is a medical emergency.
  • Wet macular degeneration. Wet macular degeneration is caused by abnormal blood vessels growing in the center of your retina of your eye and leaking excess fluid. This condition progresses rapidly and is a medical emergency.

These causes normally have additional symptoms that blurry vision after eating doesn’t. On the other hand, you might be experiencing other symptoms of diabetes or carotid stenosis along with your blurry vision after eating, but those symptoms will look very different than symptoms that go along with other eye-related causes.

For example, blurry vision followed by a pounding headache is generally caused by migraine, and blurry vision you have alongside eye itching and eye discharge is likely keratitis.

Any blurry vision that isn’t relieved by rest or that keeps returning should be evaluated by a medical professional. Sometimes, it can be a sign of a medical emergency.

Call 911 if you have blurry vision that was caused by an injury or that occurs along with:

  • eye pain
  • sudden vision changes
  • vision loss in one eye only
  • vision loss in only a certain area of your field of vision
  • paralysis one side of your body
  • facial drooping
  • difficulty speaking

It’s important to have your blurry vision evaluated by a medical professional. They’ll go over your symptoms and your health history to find a cause for your blurry vision.

You can prepare for your appointment by keeping track of factors such as:

  • how long you’ve been experiencing blurry vision
  • any other symptoms you have along with it
  • whether it’s better or worse at any particular time of day
  • whether it’s better or worse after certain activities

If you believe your blurry vision might be linked to eating, it’s a great idea to also track your meals. You can keep a log of what you eat and how your vision is impacted.

This can be a big help in seeing a connection between your blurry vision and blood sugar. This connection is sometimes one of the earliest symptoms of diabetes mellitus.

It can also help start a conversation with your doctor about diabetes. You might discuss whether you’d benefit from losing weight, quitting smoking, changing your diet, or increasing your physical activity.

Blurry vision after eating can be one of the first signs of diabetes mellitus. It happens when high blood sugar spikes cause swelling in your eye. Managing diabetes and controlling blood sugar levels can prevent blurry vision after eating.

Some people with carotid stenosis also report blurry vision after eating, but this is not considered a common symptom. Other causes of blurry vision range from mild conditions, such as allergies or conjunctivitis, to medical emergencies such as retinal detachment.

It’s a good idea to see a medical professional if you have blurry vision that lasts for more than a day or that’s accompanied by other symptoms.