Sudden blurry vision can be scary—but don’t panic. It has many possible causes. Fortunately, not all are serious.
Blurry vision can be a temporary reaction to stimuli such as bright lights or eye drops or an ongoing condition such as astigmatism or dry eye, which will cause you to be unable to see fine detail.
In some cases, vision changes such as blurry vision can signal a severe underlying condition.
To get your vision back to normal, it’s always a good idea to have a medical professional examine your eyes.
In this article, I’ll discuss the possible causes of blurry vision and its risk factors. I’ll explain how blurry vision can be diagnosed and its treatment options.
Finally, I will discuss when it is necessary to see a medical provider for your vision concerns and how K Health can help.
Causes of Blurry Vision
One of the main symptoms of astigmatism is blurred vision, whether at a close or far distance.
Astigmatism occurs when the cornea or lens has an abnormal shape, affecting how light enters your eyes.
Aside from blurry vision, other symptoms that may accompany astigmatism include:
- Squinting to see clearly
- Poor vision at night
Risk factors for astigmatism include inheriting it from your family members, nearsightedness or farsightedness, eye injury, and eye surgery.
Presbyopia, or age-related farsightedness, causes nearby objects to look blurry.
It happens when the eye’s lens stops focusing light on the retina correctly. It’s most common in middle-aged and older adults.
Some other symptoms of presbyopia include:
- Moving things far away to see them clearly
Old age is the most significant risk factor for presbyopia.
Other risk factors include farsightedness, cardiovascular disease, diabetes, and medications such as antidiuretics and antidepressants.
Dry eyes occur when your eyes do not produce enough tears for lubrication.
It generally causes discomfort and sometimes blurry vision. Other symptoms include:
The risk factors for having dry eyes include having a uterus, being aged 50 or older, wearing contact lenses, vitamin A deficiency, and medical conditions like lupus and Sjogren’s syndrome.
A medical provider or optometrist can diagnose dry eyes during an eye examination.
Viruses, bacteria, or fungi can cause eye infections.
These infections can cause blurry vision.
Conjunctivitis is a blanket term used to refer to inflammation of the eye—you may have had “pink eye” before, which is a type of conjunctivitis and can cause irritation and blurred vision.
If you have an eye infection, you may experience other symptoms alongside blurry eyes, such as:
- Bulging eyes
- Decreased eye movement
- Swollen eyelid
- Double vision
Exposure to infected individuals is the leading risk factor for infectious conjunctivitis.
If you’re around a person infected with conjunctivitis, you can avoid getting infected by washing your hands with soap and water for at least 20 seconds, not touching your eyes with unwashed hands, and not sharing personal eye care items with an infected person.
Cataracts are a cloudy area in the lens of your eyes that cause blurry vision, among other symptoms.
It affects more than 50% of adults aged 80 and above in the United States. Some of the other symptoms of cataracts include:
- Poor vision at night
- Double vision
- Increased sensitivity to light, so that lamps and light sources seem too bright
- Colors look faded
- Seeing a halo around lights
The primary risk factor for cataracts is old age — the older a person gets, the higher their chances.
Other risk factors include eye injury, previous eye surgery for glaucoma, and a family history of cataracts.
Eye injury occurs when an object, either blunt, sharp, or chemical, makes contact with the eyes.
It can cause blurry vision, pain, and in extreme cases, loss of eyesight.
Activities at home such as repairs, cooking, and cleaning can put you at risk for eye injuries. Recreational activities such as sports also increase your risk.
Some high-risk occupations include work in chemical industries and on construction sites.
Some ways to prevent eye injuries include wearing safety goggles while handling chemicals, wearing a helmet while playing impact sports, and wearing sunglasses to protect your eyes from sun rays.
Excessive computer use
Excessive computer use involves staring at screens for extended periods without breaks.
It can lead to a condition known as computer vision syndrome, which causes blurry vision.
Other symptoms include:
- Dry eyes
- Double vision
- Eye redness
- Neck and shoulder pain
These symptoms are typically temporary.
Poor lighting, poor posture, screen glare, and staring at your computer at the wrong distance and angle can put you at risk for these symptoms.
A migraine is a recurrent headache of varying intensity, usually accompanied by nausea and increased sensitivity to light.
Migraine aura, which are symptoms that occur before a migraine attack, may include blurry vision. Other symptoms include:
- Eye pain
- Seeing flashing lights or zigzags
- Temporary blind spots or colored spots
The exact cause of migraine is unclear, but genetics may play a big part.
People with migraines have different triggers, which often include stress, changes in sleep patterns, and hormonal fluctuations.
Health care providers diagnose migraines based on health history and the description of symptoms.
Diabetes is a chronic disease that affects how your body processes food into energy, or sugars.
When diabetes causes significantly high blood sugar, it can damage tiny blood vessels in the retina, which can cause your vision to be blurred. This is called diabetic retinopathy.
Hormonal changes during pregnancy may contribute to the progression of diabetic retinopathy.
High blood sugar levels, high blood pressure, high cholesterol, smoking, and being African American or Hispanic are also risk factors.
An eye specialist performs a comprehensive dilated eye exam to diagnose diabetic retinopathy.
First, drops are put in the eyes to widen the pupil so your doctor can observe any abnormalities.
A blocked artery causes strokes. This interrupts the blood supply to the brain and can cause brain damage.
It can affect a person’s vision causing blurry vision and double vision.
A temporary interruption of blood to the brain, called a transient ischemic attack, can also cause blurry vision but usually resolves within hours.
The risk factors for stroke include high blood pressure, heart disease, smoking, diabetes, and obesity.
Doctors often diagnose a stroke by conducting physical tests where they check vision, reflex, muscle strength, sensation, and coordination.
Multiple sclerosis is a chronic disease that affects the brain and spinal cord.
One of the first symptoms of multiple sclerosis can be vision problems, one of which is optic neuritis. In optic neuritis, the optic nerve is inflamed, which can cause blurred vision.
Other symptoms of optic neuritis, which usually occur in only one eye, include:
- Loss of color
- Dim vision
- Pain with eye movement
The risk factors for multiple sclerosis include a family history of multiple sclerosis, vitamin D deficiency, certain autoimmune diseases such as thyroid disease, and smoking.
Unfortunately, there’s no proven way to prevent multiple sclerosis, but you can reduce the risk by keeping stress levels low, avoiding smoking, exercising regularly, eating a healthy diet, and getting enough vitamin D.
A tumor in the brain can build pressure in the skull.
This pressure on the optic nerve can cause blurry vision, which may progress to double vision and blindness. Other symptoms include:
- Problems with balance or walking
- Nausea and vomiting
- Changes in mood and behavior
The risk factors for brain tumors include age (more common in children and older adults), gender (more common in people without vaginas than in people with vaginas), family history, environmental exposure, and exposure to infections.
Magnetic resonance imaging (MRI) is used to diagnose a brain tumor.
Pregnancy complications like preeclampsia can cause blurry vision.
This occurs when pregnant people have persistent high blood pressure and protein in their urine. It typically occurs during the later stages of pregnancy.
There may be no symptoms, but blurred vision is top on the list when there are.
Providers diagnose preeclampsia by taking blood pressure readings after 20 weeks of pregnancy and testing for the presence of protein in the urine.
There’s no known way to prevent preeclampsia.
Lifestyle changes such as losing weight, exercising regularly, and controlling blood pressure and blood sugar levels may help.
People with certain health conditions that can affect the eyes, such as astigmatism and cataracts, are at a higher risk of having blurry vision.
If you have diabetes, you should discuss proper blood sugar management strategies with your doctor as high blood sugar can affect the eyes, increasing the risk of blurry visions.
People whose jobs involve using the computer excessively or people who always stay in front of a screen may also have a higher risk of developing vision problems like blurry vision.
To diagnose you, your doctor will first ask about your symptoms.
They may want to know when you first noticed the blurred vision as well as take your medical history.
Doctors often check for family history of eye conditions as well when diagnosing vision problems.
The doctor will also run a physical examination to check for swellings, foreign objects in the eyes, or other abnormalities.
To ascertain the problem, your doctor may further order eye tests such as:
- Ophthalmoscopy (to look at your retina, optic disk, and eye blood vessels)
- Refraction test (to know if you need a prescription lens)
- Tonometry (to measure the pressure inside your eyes)
If your doctors suspect an infection may cause your blurred vision, they may order blood tests to check for infectious agents in the blood.
They may also run other tests to check for other possible underlying conditions.
Treatment for blurry vision will vary depending on the cause of your vision problems.
Your doctor will first run different tests to determine the underlying cause and treat it.
For instance, if dry eyes caused your blurry vision, your doctor may prescribe for you eye drops, moisturizing gels, and lotions, and if a bacterial infection caused it, they would prescribe for you an antibiotic.
Medications, getting enough rest, and adopting the 20-20-20 rule (spend 20 minutes looking at the screen and looking at an object 20 feet away for 20 seconds) can also help.
Because there are many possible causes of blurry vision, it can be difficult to prevent.
However, there are some lifestyle management steps you can take to reduce your chances of having blurry vision, such as:
- Reducing your screen time, taking frequent breaks, and wearing anti-glare glasses when looking at a screen
- Going for regular eye examinations
- Monitoring your blood sugar levels and keeping them in check if you have diabetes
- Eating foods that are rich in vitamin A (e.g., carrot and liver) and foods that are high in omega-3 fatty acids (e.g., tuna fish) which are good for the eyes
- Wearing UV-protective sunglasses when going out in the sun
- Drinking plenty of fluid to keep the body (including the eyes) hydrated
- Using humidifiers to improve air quality
- Cleaning your contact lens to prevent infection
When to See a Medical Provider
It’s best to discuss blurry vision with your eye doctor or primary care provider to rule out underlying health conditions.
Your doctor will be in the best position to tell you if you need treatment or not. For many of the causes, early diagnosis is vital to prevent the progression of the condition.
How K Health Can Help
Are you experiencing sudden blurry vision? You may need to speak to a doctor. Did you know you can get affordable primary care with the K Health app?
Download K to check your symptoms, explore conditions and treatments, and, if needed, text with a healthcare provider in minutes.
K Health’s AI-powered app is HIPAA compliant and is based on 20 years of clinical data.
Frequently Asked Questions
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Causes, Occupational Risk and Socio-Economic Determinants of Eye Injuries: A Literature Review. (2021).
Diabetic Retinopathy. (2022).
Diabetic Retinopathy and the Effect of Pregnancy. (2010).
Evidence-Based Prevention of Preeclampsia: Commonly Asked Questions in Clinical Practice. (2019).
Presbyopia: Overview. (2020).