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Understanding Blurred Vision

Blurred vision, or blurry vision, is when you can’t see things clearly. In other words, your vision is not clear and sharp. 

Many things can cause blurred vision, including common problems like eye strain (tired eyes), as well as more serious conditions that require immediate treatment. You should seek medical attention immediately for sudden blurred vision or blurry vision accompanied by other symptoms like severe eye pain, double vision, or problems with speech or movement.

Cloudy Vision versus Blurry Vision

There is a slight difference between blurred vision and cloudy or hazy vision. Both cause you to not see things clearly. However, blurry vision is when things look out of focus, and squinting may help bring things into focus. Hazy or cloudy vision feels like looking at things through a haze or fog. Some of the same underlying conditions can make vision blurry or cloudy. 

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Common Misconceptions About Eye Health

According to the American Academy of Ophthalmology, here are some of the most common myths and misconceptions about eye health:

• Eating carrots improves vision. Carrots are a good source of vitamin A, which is important for vision, but you only need a small amount of vitamin A. Other foods are rich sources of this vitamin as well, such as leafy green vegetables. 

• Reading in dim light can harm your eyes. This is a myth. However, reading in dim light can lead to tired eyes. Read in a well-lit area to prevent eye strain.

• Using computers damages the eyes. Blue light from a computer screen does not damage the eyes, but looking at screens for long periods without breaks can cause dry eyes and eye strain. Blink frequently or use artificial tears to lubricate your eyes.

Importance of Early Detection

Sometimes, blurred vision is temporary and resolves on its own, for example, when it is due to tired eyes. At other times, the symptom develops gradually and then persists or worsens, which may indicate an underlying medical condition requiring appropriate diagnosis and treatment. Certain health conditions cause sudden blurred vision and are medical emergencies. It’s vital to seek emergency medical care if blurry vision comes on all of a sudden, especially if you also experience a severe headache, eye pain, muscle control difficulty, and seeing lights or shadows in your vision.

Causes of Blurred Vision

Refractive Errors and Eye Strain

A refractive error or eye strain is the most common cause of blurred vision. Eye strain or tired eyes can cause blurred vision, for example, after looking at a computer screen for a long time or reading in dim light. 

Refractive errors are conditions in which your eyes cannot form properly focused images. Examples include myopia (nearsightedness), hyperopia (farsightedness), presbyopia (age-related farsightedness), and astigmatism (where the cornea or lens of the eye has an egg-shaped curvature instead of spherical). 

Eye Conditions That Can Cause Blurry Vision

• Dry eye syndrome. Symptoms may include blurred vision, redness, itching, and pain. Blurry vision improves with blinking.

• Common eye infections such as infectious conjunctivitis cause symptoms such as eye redness, swelling, pain, itching, watering, discharge, photophobia (light sensitivity), and vision changes (blurry or double vision).

• Cataract. An opaque or cloudy eye lens is called a cataract. It can cause blurry vision, halos around lights, and loss of contrast in vision.

• Age-related macular degeneration. This eye condition occurs in older adults and causes blurry central vision and wavy lines. It can lead to a gradual loss of vision. Learn more about macular degeneration.

• Glaucoma is an eye disorder in which the pressure inside the eye (intraocular pressure or IOP) is increased, causing blurred vision, eye pain, and halos around lights, among other symptoms. Left untreated, it can lead to permanent damage of the optic nerve and permanent vision loss.

• Diabetic retinopathy (diabetes-related eye damage) can cause symptoms such as eye pain, redness, floaters, blurred vision, and problems with night vision (seeing in the dark).

• Optic neuritis is an inflammation of the optic nerve that can cause blurry eyesight and pain with eye movement. It can occur on its own or in association with multiple sclerosis or infectious diseases such as herpes zoster virus, Cytomegalovirus, Lyme disease, or other bacterial or fungal infections.

• Retinal detachment is a separation of the retina (light-sensitive layer at the back of the eye) from its supporting layers. Symptoms of a detached retina can include blurry vision, flashing lights, eye floaters, and decreased peripheral vision (like a shade placed across your visual field).

• Retinal vein occlusion (blockage in the blood vessels that carry blood out of the eye). Symptoms can include blurry vision and vision loss in one eye that develops suddenly.

• Hyphema is bleeding inside the eye and collection of blood in the front part of the eye between the cornea and iris. It occurs due to eye trauma and in people with sickle cell disease. Symptoms may include a reddish tinge to the eye, blurred or distorted vision, nausea, and vomiting.

• Eye injuries such as a corneal abrasion can affect vision and cause eye pain, redness, swelling, watering, light sensitivity, and blurriness.

• Contact lens use. Dirty contact lenses, an outdated prescription, a new contact lens prescription, or dry eyes related to contact lens use can lead to blurriness of vision.

• Certain genetic disorders, such as Leber hereditary optic neuropathy and dominant optic atrophy, can affect the optic nerve and cause blurry vision.

• Severe vitamin A deficiency can lead to corneal dryness, scarring, ulcers, and blindness. This condition is uncommon in developed countries such as the United States.

Blurred Vision Associated With Other Medical Conditions

Some of the non-eye conditions that can cause blurred vision include:

• Hypertension (high blood pressure)

• Hypoglycemia (low blood sugar) 

• Migraine headache

• Psoriasis

• Multiple sclerosis

• Parkinson’s disease

• Brain tumor

• Concussion or traumatic brain injury (TBI)

• Stroke or transient ischemic attack (TIA)

• Postural orthostatic tachycardia syndrome (POTS)

• Preeclampsia

• Gestational diabetes (high blood sugar in pregnancy)

• Stress and anxiety

• Medication side effects, for example, from antihistamines, corticosteroids, and antimalarial drugs

Causes of Sudden Blurry Vision Requiring Emergency Treatment

Sudden blurry vision can be a symptom of life-threatening problems that are medical emergencies, such as stroke, hypertensive crisis (dangerously high blood pressure), concussion, retinal detachment, retinal vein occlusion, eye injury, serious eye infection such as infectious keratitis, or hyphema (bleeding in the eye).

Symptoms and Diagnosis

Key Symptoms To Watch For: When To Seek Medical Attention?

Seek immediate medical attention if you have:

• Sudden blurred vision

• Vision loss

• Severe or sudden eye pain

• History of trauma (eye injury or head injury)

• Difficulty speaking or moving

Diagnostic Tests and Procedures

An optometrist or ophthalmologist (eye doctor) can make an accurate diagnosis of the cause of your blurred vision based on your symptoms, risk factors, medical history, and eye exam. Your healthcare professional may also order diagnostic tests, such as blood tests, to detect underlying health problems that can cause blurry vision.

Eye exams used to diagnose blurry vision may include:

• Visual acuity testing

• Visual refraction eye test

• Slit-lamp examination

• Ophthalmoscopy or retinoscopy

• Corneal topography

• VFA testing to find a visual field defect or blind spots

• Air puff test (no-contact tonometry)

• Color blindness test

• Amsler grid

• Fundus photography

• Optical coherence tomography (OCT)

• Fluorescein angiography

• Heidelberg retinal tomography 

Treatment and Management: How is Blurred Vision Treated?

Blurred vision is a symptom of certain eye conditions and other health conditions. Treatment for blurry vision, therefore, depends on the cause. It may include:

Corrective Lenses 

Refractive errors are a common cause of blurred vision, and they can be treated with eyeglasses or contact lenses.

Medications

Your eye doctor may prescribe eye drops or other medications to treat the underlying condition, for example:

• Lubricating artificial tears for dry eyes.

• Antibiotic eye drops such as tobramycin or bacitracin to treat bacterial eye infections.

• Pilocarpine hydrochloride (Vuity) eye drops for presbyopia (age-related farsightedness).

• Eye drops for glaucoma, such as bimatoprost (Lumigan), travoprost (Travatan Z), latanoprost (Xalatan), tafluprost (Zioptan), betaxolol (Betoptic) and timolol (Timoptic) to reduce eye pressure.

• Antihypertensives for high blood pressure.

• Anti-migraine medicines for a severe headache disorder.

Surgical Interventions

Surgical procedures may include: 

• Cataract surgery 

• Vision correction LASIK (laser-assisted in situ keratomileusis) surgery for refractive errors

• Laser treatment for angle-closure glaucoma

• Corneal or retinal surgery

• Surgery to repair eye injuries

Management of Underlying Health Conditions

As mentioned, certain non-eye conditions can cause blurred vision. If this is the case, your doctor will recommend treatments to manage the underlying health problem that is causing blurriness of vision.

Preventative Measures for Blurred Vision

Regular Eye Exams and Monitoring

The American Academy of Ophthalmology and the National Eye Institute recommend regular eye exams. The guidelines are as follows:

• Seek immediate medical help or make an appointment for an eye examination if you have any eye symptoms, changes in vision, or eye injury. 

• Adults with no risk factors or symptoms of eye disease should get a baseline comprehensive eye examination at age 40. In the absence of any symptoms, the frequency of eye evaluations should thereafter be every 2 to 4 years between ages 40 and 54; every 1 to 3 years between ages 55 and 64; and every 1 to 2 years after age 65 years. 

• Periodic comprehensive eye exams are recommended for timely diagnosis and early treatment in people who are symptom-free but at a high risk of eye problems due to health conditions such as diabetes or hypertension or a family history of eye diseases.

• Those with a higher risk of certain eye conditions, such as glaucoma, should get a comprehensive eye evaluation every 2 to 4 years before age 40; every 1 to 3 years between ages 40 and 54; and every 1 to 2 years after age 55.

Healthy Lifestyle and Diet Tips and Protective Measures for Eye Health

• Take frequent breaks when working on the computer and blink frequently to avoid dry eyes and eye strain.

• Use lubricating eye drops or artificial tears for dry or irritated eyes.

• Clean your contact lenses properly.

• Protect your eyes from ultraviolet (UV) light rays by wearing sunglasses.

• Avoid exposure to allergens like dust and smoke.

• Wear eye protection while playing sports or doing hobbies that can damage your eyes. 

• Eat an eye-healthy diet with a variety of foods that include essential vitamins and minerals.

• Stay well hydrated.

Check out Vision Care: 5 Tips For Healthy Eyes.

FAQs About Blurred Vision Causes and Treatments

What To Do If Your Vision Is Getting Blurry?

Make an appointment to see your primary care physician or eye doctor if your vision is getting blurry gradually. Seek immediate medical help for sudden blurry vision.

What Can Cause Blurry Vision All of a Sudden?

Sudden blurred vision can be a sign of stroke, which is a medical emergency. It can also occur if you have very high blood pressure, a head injury, eye injury, eye infection, or bleeding inside the eye. Seek medical attention without delay if you develop blurred vision suddenly.

Can Anxiety or Stress Cause Blurry Vision?

Yes, mental stress and anxiety can cause both mental and physical symptoms, including temporary blurry vision.

Can Dehydration Cause Blurred Vision?

Dehydration does not directly cause blurred vision, but it can cause dry eyes, which can cause vision problems including blurry vision.

What Causes Brain Fog and Blurred Vision?

Potential causes of brain fog and blurred vision include low blood sugar (hypoglycemia) and neurological disorders such as multiple sclerosis.

What Causes Dizziness and Blurry Vision?

Dizziness and blurriness of vision can be symptoms of migraine headache or low blood sugar.