Headaches and blurry vision are a lot alike. The cause of either can seem like a mystery. And when it strikes, you may wonder if it’s just an annoyance or if it could signal a more serious problem.

The obvious culprit is a change in your vision, resulting in a need for an updated prescription in your eyeglasses or contact lenses. Feeling stressed at work, staring at a computer screen all day, or sleeping poorly can all result in blurry vision, too. But some other blurry vision causes aren’t so benign.

“Blurry vision that comes on suddenly always requires an immediate optometrist visit,” says Whitney Wallace, O.D., an optometrist at America’s Best Contacts & Eyeglasses in Bolingbrook, Illinois. “It could indicate something that needs urgent attention, like an infection or a retinal tear or detachment.”

But even blurry vision that comes on gradually should be checked out, she notes. It’s important to rule out a potential underlying eye condition that may worsen if left untreated.

Here are five blurry-vision scenarios where it’s worth contacting your optometrist.

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1. The Blurriness Came on Suddenly

While blurred vision that occurs gradually should also be checked out, it’s not as worrisome as sudden blurriness.

“If you wake up in the morning and your vision is blurry out of one eye, you should see your optometrist right away because it’s an indication that may be swelling at the front of the eye, which could be due to retinal problems in the back of the eye",” says Dr. Wallace. “I’ve had patients come in in this situation just thinking their prescription needs to be updated, when there’s a real eye disease at the front of their eye that needs to be taken care of.”

The most common culprits? An eye infection or retinal tear or detachment, says Dr. Wallace. That’s when your retina gets torn or ripped away from its normal position, she says. But it could also be the sign of an eye bleed, or even an eye stroke. Your optometrist is the best person to make the call and decide where to refer you if you need more specialized care.

2. You’ve Got Sudden New Floaters Along with Your Blurry Vision

Floaters themselves are not a cause for concern. They are the small dark shapes that literally “float” across your vision. They can look like dots, threads, squiggles, or even cobwebs.

Floaters are caused by normal changes in your eyes. As you get older, the tiny strands of the gel-like fluid in your eye (known as vitreous) stick together and cast shadows on your retina, the light-sensitive layer of tissue at the back of your eye. Voila! You have a floater.

While most of the time floaters are benign, there are a few instances when they could signal a retinal tear or detachment. If you have these symptoms, call your optometrist right away:

• You suddenly see new floaters
• You see flashes of light in your vision
• Your floaters are accompanied with blurriness

“We can dilate your eyes and see immediately whether it’s a retinal problem versus normal vitreous,” says Dr. Wallace. If it’s the former, you’ll likely be referred to a retina specialist for treatment and care.

Press play for a peek at what it’s like to experience floaters:

3. Along with Your Blurry Vision, Your Eyes Are Red and Painful

Usually, this is due to some sort of irritation or infection, says Dr. Wallace. One of the most common causes is conjunctivitis (pink eye), a viral or bacterial infection in your eye that causes redness, crustiness, and swelling.

Viral conjunctivitis will get better on its own, but the bacterial version may require antibiotic eye drops. You’ll also need to avoid your contact lenses until your symptoms have resolved.

Another cause is dry eye, which research suggests affects more than 16 million Americans. Women are twice as likely to develop it as men, and risk rises with age. Mild cases can usually be managed with over-the-counter artificial tears. Your optometrist can also prescribe eye drops to increase tear production, while more severe cases may require surgery.

If you have dry eye symptoms, it’s important to get it diagnosed and treated. Chronic dry eye can damage the front surface of the eye over time, according to the American Optometric Association.

Blurry vision along with a red eye that’s light-sensitive could also signify uveitis, where the middle layer of the eyeball gets inflamed. Since this part of the eye is filled with blood vessels, the swelling can damage eye tissue and lead to permanent vision loss.

Your optometrist can treat this issue with prescription eyedrops. But because uveitis could signal another underlying condition, such as an autoimmune disease (rheumatoid arthritis, for instance), your eye doctor may also refer you to other medical specialists for more testing.

4. You’ve Been Sleeping All Night in Your Contacts

Your eyes need to breathe. That doesn’t happen when you wear contacts all day. That’s why your eyes require some time at night to breathe.

But when you doze off with your contacts in, your eyes don’t get a chance to breathe. Your corneas may swell, which can cause irritation, blurred vision, or an infection.

You don’t need to panic if you wake up and realize you slept in your contact lenses — but you should call your eye doctor if you’re experiencing discomfort hours or even a day later. “We’ll want to see you right away and evaluate your eye to see if there are any signs of eye infection,” says Dr. Wallace.

If you do tend to dose off with your lens in, talk to your optometrist. You may be a candidate for some types of extended wear contact lenses that allow occasional overnight wear. These lenses permit more oxygen to reach your eyes, which allows your corneas to get the nutrients they need to stay healthy.

5. You’re Over Age 50 and You’ve Noticed Faint Blurry Vision

If you’ve noticed periods of time where your vision has been faintly blurry but then reverts to normal, it’s time to see your optometrist. You might also notice a gradual blurring that’s worsening over time.

“It could be a sign of eye disease,” says Dr. Wallace. This includes conditions like:

• Age-related macular degeneration. This is the most common cause of vision loss in older adults, and affects your central vision, so that you can’t see what’s right in front of you.
• Diabetic retinopathy. If you have diabetes that’s poorly controlled (or undiagnosed), the condition can weaken the blood vessels in your retina. That leads to blurry vision and, over time, potentially even blindness.
• Glaucoma. This disease causes fluid to build up in your eye and puts pressure on the optic nerve, leading to blurry vision and vision loss.
• Cataracts. This condition is a normal part of aging — your eyes develop cataracts that cause your lenses to become clouded and hard to see through. Symptoms include blurry vision and seeing halos around lights when it’s dark.

With all of these diseases, prompt diagnosis is key to improve blurry vision and prevent further vision loss.

Medically reviewed by Whitney Wallace, O.D.

See our sources:
Eye floaters overview: National Eye Institute
Prevalence of dry eye disease: American Optometric Association
Dry eye overview: American Optometric Association
Uveitis overview: American Academy of Ophthalmology
Blurred vision overview: Cleveland Clinic