Sudden Blurry Vision in Both Eyes: Causes, Risks, and When To See a Doctor

Blurry Vision: What Does It Mean?

Blurry vision is the loss of sharpness or crispness in the ability to see. Objects around you may seem hazy, and you may even find it difficult to read smaller letters. Blurry vision can be due to various reasons. Typically, a problem with one eye, such as the retina, cornea, or optic nerve, can cause sudden blurry vision in that eye. However, if the blurred eyesight progresses gradually, especially in both eyes, the reasons may not be confined to the eye itself. And in case you are wondering, why is my vision blurry all of a sudden? It could be due to a more serious underlying health condition related to your brain, nerves, or even a systemic disease. 

Blurred Vision: Gradual versus Sudden

Upon closer examination, the gradual progression of blurriness in both eyes can be attributed to age-related factors, such as cataracts or prescription errors. Symptoms develop over months or years, with minimal impact on your daily routine. However, a sudden blurred vision in both eyes occurs within seconds or minutes. It's indeed a medical emergency and cannot be ignored. So, see your healthcare provider immediately, as left untreated, it can cause permanent vision loss. 

What Causes Sudden Blurry Vision in Both Eyes?

Experts categorize the causes of sudden blurry vision in both eyes as systemic, neurological, or eye-related (bilateral) conditions. We elaborated on them below.

Systemic Causes

Our body functions as a connected system, and certain whole-body issues indeed impact our ability to see clearly. These systemic conditions can disrupt the normal functioning of the eyes and may require immediate medical attention.

• High blood pressure: Certain health conditions contribute to elevated blood pressure levels that persist for a prolonged period. This damages the sensitive blood vessels of the eyes, obstructing the nutrient and oxygen supply retina and other parts of the eye. In others, the pressure build-up can weaken or stiffen blood vessels in the retina, causing them to rupture.^[1] Either case may lead to permanent vision loss. Conversely, in some patients, high blood pressure can cause fluid build-up or altered blood flow, resulting in temporary blurriness. This is characterized by the sudden onset of blurry vision in both eyes, accompanied by floaters, headaches, and dark spots. 
• Diabetes: High blood sugar causes swelling of the eye lens and damages the sensitive blood vessels of the retina (diabetic retinopathy). A swollen eye lens cannot refract light as it normally does, and therefore, produces blurry images. Weakened blood vessels cause fluid leakage, causing distorted vision. In some patients, it causes the formation of new blood vessels, which may lead to scar formation on the retina. ^[2] In others, uncontrolled blood pressure, which persists over longer periods, elevates intraocular pressure, a condition known as glaucoma, affecting the optic nerve. Although vision problems due to glaucoma follow a progressive pattern, most cases go unnoticed, resulting in a sudden vision problem. The sudden blurry vision in both eyes diabetes, presents as hazy eyesight, with floaters and difficulty seeing colors. 
• Multiple sclerosis: Multiple sclerosis (MS) is an autoimmune condition that affecting the myelin sheath of nerve fibers. MS causes vision problems due to scarring or demyelination of the optic nerve. The optic nerve transmits the eye’s captured images to the brain for processing, and a damaged myelin sheath causes inflammation. Candidates experience double vision, reduced color vision, and discomfort during eye movements. ^[3] 
• Uveitis: An inflammation of the eye’s middle layer caused by infection or autoimmune disease is uveitis. This obstructs the blood and nutrient supply to the eye's structures, such as the iris, cornea, retina, and vitreous humor. Nutrient deprivation can damage the retina and optic nerve, leading to permanent vision loss. It is characterized by pain, light sensitivity, and redness and should not be ignored.^[4]    
• Migraine: Migraine, in most cases, is mistaken solely as an intense headache. Very few people are aware of its other side, which includes vision-related symptoms. Visual disturbances including flashes of light, patterns, and blind spots often precede a headache. This condition is known as retinal or ocular migraine, and its symptoms typically subside within 10 to 30 minutes, followed by an intense headache.^[5]   
• Autoimmune problems: Vision problems resulting from autoimmune conditions occur when the body’s immune system mistakenly attacks healthy eye tissues or optic nerves, causing inflammation and damage. Vision problems arise due to inflammation of the small blood vessels in the eye, the protective covering of the optic nerves, or the retina itself. Lupus, optic neuritis, and autoimmune uveitis are a few conditions that can cause vision problems.     
• Pregnancy: Sudden blurry vision in both eyes pregnancy can be serious. It is indeed an indication of the underlying serious conditions like high blood pressure, uncontrolled blood sugar levels, or imbalances in fluid retention due to hormonal changes. Extremely high blood pressure, especially during pregnancy, may cause organ damage, including the eyes. Attending regular prenatal care check-ups will help you avoid severe circumstances.   

Brain and Nerve-Related Causes

Light enters the healthy human eye and is refracted by the lens to fall on the retina. After capturing light, the retina passes the message through the optic nerves to the brain’s vision center at the back of the head. Most vision problems originate in the eyes, but issues in the brain can also cause problems. When the brain can’t process the signals from the eyes properly, it can lead to vision problems, even if the eyes themselves are healthy.

• Stroke: A stroke occurs when the brain's blood supply is interrupted, either due to a blockage or a rupture in a blood vessel, often due to narrowing or the formation of clots, or by a ruptured vessel. Strokes are generally classified into three main types: ischemic stroke, because of a blocked blood vessel; hemorrhagic stroke, due to a burst or leaking vessel; and transient ischemic attack (TIA), a temporary blockage that serves as a warning sign for a possible future stroke. When the occipital lobe, the brain region responsible for visual processing, is affected, it can lead to sudden blurred vision and dizziness. This type of vision loss is usually painless and may feel like looking through a smudged or distorted window. It’s often accompanied by confusion, difficulty speaking, and trouble moving the eyes or one side of the body.
• Optic neuritis: Optic nerves carry information from the retina to the brain, and any damage or inflammation causes disruption of the information flow. As a result, candidates experience vision problems ranging from partial to complete blindness. Optic neuritis is more likely to cause vision loss in one eye at a time. However, sudden blurred vision in both eyes can also occur.  
• Optic chiasm disorders: The optic chiasm is a crucial part of the brain that processes information from both eyes. Damage to the optic chiasm, often caused by pituitary tumors or vascular problems, leads to chiasm disorders. Vision problems due to chiasm disorders typically begin with vision loss in the outer temporal halves of both eyes, characterized by reduced sharpness and increasing blurriness in both eyes.^[6]    
• Damage to the visual cortex: The visual cortex, situated at the back of the brain, receives signals from the retina via the optic nerves. It is specifically involved in processing visual information, and damage to the visual cortex hurts its ability to process images. Note that the severity of vision loss varies with the extent of damage.

Eye-Related Problems

Each eye captures a slightly different image. The brain merges this information to create a single, clear picture. This coordinated teamwork is essential for normal vision. However, problems in one or both eyes can sometimes lead to sudden blurry vision in both eyes. Generally speaking, eye-related conditions affecting both eyes simultaneously are uncommon. However, certain issues or body conditions increase the risk factor.

• Diabetic retinopathy: High blood pressure damages the retina due to the swollen, leaky blood vessels, causing lesions or the growth of new blood vessels. While this condition most commonly affects both eyes simultaneously, its severity may vary. 
• Retinal detachment: The retina, a light-sensitive layer, loses its blood supply when it detaches from the back of the eye. Retinal detachment generally happens in one eye at a time. However, the incidence of such a situation in both eyes does exist, specifically in candidates suffering from connective tissue disorders.^[7] 

Less Serious Causes for Sudden Blurry Vision in Both Eyes

Here are a few instances or conditions that cause sudden blurry vision in both eyes. 

• Sudden blurry vision in both eyes after waking up lasts for a few minutes and is usually painless. In general, it happens when you suffer from dry eyes, eye allergies, fluid build-up in the cornea, or when you sleep with contact lenses. Try blinking for a few minutes and splash cold water on your face to feel normal again.
• Sudden blurry vision in both eyes for a few seconds is less severe and can be due to eye strain. Prolonged screen time, or reading in dim light, can cause this problem. Taking breaks, spending time in adequate lighting, staying hydrated, and using artificial tears (also known as eyedrops) can help you manage this condition. 
• Sudden blurry vision in both eyes and headache can sometimes occur due to less serious conditions, such as nasal congestion or stress. This relieves with at-home remedies. However, this cannot be confused with the headache associated with migraine aura. It is often experienced as blind spots and flashes of light. 

Sudden Blurry Vision in Both Eyes Child

Simple refractive errors, eye infections, or, in rare cases, serious conditions such as retinal detachment typically cause blurry vision in both eyes in children. Parents should look for other symptoms besides blurred vision. Prompt action is necessary to prevent severe consequences. Here, we discussed a few key points to enhance your understanding.

• Blurry vision in both eyes with no other significant symptoms can be due to emerging refractive errors or eye strain. Myopia, hyperopia, or astigmatism can be corrected using prescription glasses or contact lenses. 
• Blurry vision in one or both eyes, accompanied by redness and pain, following an eye injury, can be caused by a corneal abrasion. The cornea, the clear, transparent front layer of the eye, may experience a superficial scratch, which requires medical attention. 
• Blurry vision in both eyes, accompanied by sensations of itchiness and discharge, can be due to eye infections such as conjunctivitis. To offer relief, healthcare professionals recommend antihistamines, antibiotics, and artificial tears (eyedrops), depending on the case.   

In general, the sudden blurred vision in both eyes can be a sign of an underlying systemic or neurological condition. Rarely is it due to eye-related causes, and it should not be ignored. 

Blurry vision in both eyes isn't something to brush off. It could be a warning sign from your body of something more serious. At Envoy Health, we connect you with trusted eye and neurological specialists quickly and seamlessly so you don't lose precious time. Take the first step toward answers and peace of mind. Sign up with Envoy Health today because your vision is too important to wait. 

What To Expect During the Evaluation?

The ophthalmologists will understand your symptoms and recommend certain tests based on them. These include 

• Blood pressure and blood sugar testing to rule out underlying systemic causes.
• Neurological examination to detect the brain and nerve functioning or associated defects.
• Comprehensive eye examination to rule out refractive errors, corneal, or retinal issues.
• Imaging tests, such as MRI and CT scans, are used for detecting abnormalities in the brain and optic nerve. 

Sudden Blurry Vision in Both Eyes Treatment

Ophthalmologists and healthcare professionals propose the appropriate treatment depending on the identified cause.  

• Prescription glasses or contact lenses are recommended based on the existing refractive errors.  
• Laser surgery is used to correct corneal problems, retinal detachments, or diabetic retinopathy.
• Surgical procedures will be performed to remove the tumors and correct the damage to the brain and the visual cortex.   
• Medications are generally prescribed to treat underlying health conditions such as diabetes, high blood pressure, or migraine. 
• Corticosteroids, immunosuppressants, and targeted immunotherapies are recommended for managing autoimmune and inflammatory conditions.    

How To Fix Blurry Vision Naturally for Both Eyes?

Blurry vision in both eyes, in most cases, is due to systemic causes. While treatment is specifically based on the underlying cause, candidates can avoid these serious conditions by following some basic precautionary steps. Not only that, but simple lifestyle changes will also help alleviate the less severe causes of blurred vision.

• Take simple breaks from screen time, and prefer reading in a room set up with adequate lighting.
• Keep yourself hydrated, or use artificial eyedrops to keep your eyes moist and free from irritation. Avoid dry and dusty environments.
• Eat a healthy diet, quit smoking, and follow a regular exercise routine. While this nourishes your body and eyes, it also reduces your risk of lifestyle diseases, such as high blood pressure or diabetes. 
• Reduce stress and practice eye exercises, such as gentle eye massages, simple rolling, and focusing on distant and close-up objects.   
• Get regular health screenings, especially if you have crossed the 40-year mark. This will help you identify systemic issues early on and act promptly before they worsen or have a negative effect on your eye health.   

Final Word!

Sudden blurry vision in both eyes can be alarming, but understanding the possible causes is the first step toward getting the right care. While it may sometimes result from minor issues, such as refractive errors or eye strain, it can also signal more serious conditions affecting the eyes, brain, or overall health. If you or someone you know experiences sudden changes in vision, especially in both eyes at once, it’s important to seek prompt medical attention. Early diagnosis can help prevent complications and protect your vision.

Worried about sudden blurry vision in both eyes? Get the answers you need fast. With Envoy Health, you’ll be connected to trusted specialists in eye and neurological care, backed by personalized support every step of the way. Sign up today and take control of your health with confidence and clarity.

References

1. Impact Of Arterial Hypertension On The Eye: A Review Of The Pathogenesis, Diagnostic Methods, And Treatment Of Hypertensive Retinopathy
2. Vision Loss And Diabetes
3. Vision Problems In Multiple Sclerosis
4. Uveitis
5. Retinal Migraine Headache
6. Neuroanatomy, Optic Chiasm
7. How Common Is It To Get Retinal Detachments In Both Eyes