Causes of Blurry Vision and Headache

Blurry vision and headaches often occur together with migraine or cluster headaches, or these symptoms may indicate eye strain. Additionally, blurry vision combined with a headache can sometimes indicate an underlying health issue or emergency condition.

Common causes of blurry vision and headaches are migraines, eyestrain, and other correctable vision issues. Examples of emergency causes include a stroke, dangerously low blood sugar, traumatic brain injury, or carbon monoxide poisoning.

Common Reasons for Headaches With Vision Changes

Headaches can sometimes cause blurry vision and other vision problems. This is especially true with migraines and cluster headaches.

Migraine Headache

A migraine headache can cause intense pain in and around your eyes, as well as vision changes.

An aura may occur before the actual headache. Auras typically lasts about 20 minutes and can include visual symptoms such as:

• Blurry vision
• Flashing lights
• A rainbow of lights
• A zig-zag pattern of shimmering lights

Some people who experience a migraine aura never develop the actual headache. This makes diagnosing visual problems difficult. 

Migraines can also cause tingling or numbness of the skin. People with severe migraines may experience the following symptoms:

• Nausea
• Vomiting
• Light sensitivity

Medications, certain foods, smells, loud noises, and bright lights can trigger migraines.

Treatment options for migraines include:

• Preventative treatment to prevent migraines from occurring (avoiding specific triggers and daily medications),
• Over-the-counter pain medications such as acetaminophen and ibuprofen (e.g., Tylenol and Motrin, respectively)
• Prescribed rescue medications such as triptans
• Anti-emetic (nausea and vomiting) medications such as metoclopramide
• Intravenous (IV) medications in a healthcare setting for severe migraines

Cluster Headache

Cluster headaches are severe headaches that occur in clusters. They typically cause pain around the eyes. The pain often travels down the neck to include the shoulder. Other symptoms include:

Cluster headaches may occur daily for several months at a time, followed by a long period without headaches.

The exact cause of cluster headaches is unknown.

Treatment for cluster headaches includes:

• Prescription triptans
• Steroids to reduce inflammation
• Breathing 100% oxygen
• Prescription dihydroergotamine (this medication should not be used with triptans)

Emergency Causes of Blurry Vision

In some cases, blurry vision can indicate a more serious condition and possible medical emergency.

Stroke

A stroke occurs when a blood clot travels to the brain, interrupting blood flow, or when a blood vessel ruptures and causes bleeding in the brain.

A stroke can lead to many symptoms, including blurry vision and a painful headache. Prompt care, ideally within an hour, is crucial to improve prognosis and help reduce disability.

The warning signs of a stroke include:

• Numbness or weakness of face, arm, or leg
• Confusion or difficulty speaking (such as slurred speech) or understanding speech
• Trouble seeing in one or both eyes
• Dizziness, loss of balance, or difficulty walking
• A severe headache

The location of the stroke in the brain affects the area of visual disturbances. For example, damage to the right side of the brain typically causes left-sided vision loss, whereas damage to the left side causes right-sided vision loss.

Stroke treatment depends on the type of stroke and how quickly it is caught. The most common cause of stroke is an ischemic stroke (blood supply cut off, typically by a clot). A medication called tissue plasminogen activator (tPA) is the first-line treatment for ischemic stroke.

If the stroke is hemorrhagic (bleeding in the brain), treatment is usually surgical and depends on how much you are bleeding and the location of the hemorrhagic stroke.

Hypoglycemia

If blood sugar levels drop too low, known as hypoglycemia, it can become a medical emergency if not treated promptly.  Hypoglycemia is blood glucose below 70 mg/dL. Headache can be a symptom of low blood sugar, and other common symptoms include:

• Fast heartbeat
• Shaking
• Sweating
• Nervousness or anxiety
• Irritability or confusion
• Dizziness
• Hunger

Hypoglycemia most commonly occurs in people with diabetes but can also be due to other conditions or factors such as medications or drinking alcohol.

Individuals with blood sugar less than 70 mg/dL but greater than 55 mg/dL can typically follow the 15-15 rule. This rule involves consuming 15 grams of carbs, waiting 15 minutes, re-checking blood sugar, and repeating this process until blood sugar has increased above 70 mg/dL.

Injectable glucagon kits are available for individuals at risk of significantly low blood sugar below 55 mg/dL. However, individuals with severely low blood sugar may not be able to inject the glucagon themselves. Seek emergency medical care after a glucagon injection.

Your healthcare provider can instruct you on the best way to increase your blood sugar if you are at risk of low blood sugar and when to seek emergency care.

Head Trauma

A traumatic brain injury (TBI) can cause headaches and blurry vision, as well as several other symptoms, such as nausea, vomiting, and dizziness. It’s essential to seek medical care after a head injury to determine the extent of the injury and for careful monitoring during recovery.

Treatment depends on the severity of the head trauma and may include:

• Brain rest
• Medications to prevent seizures
• Over-the-counter or prescribed pain medications
• Diuretics to reduce fluid build-up in the brain
• Other treatments as indicated depending on symptoms

Giant Cell Arteritis

Also known as temporal arteritis, giant cell arteritis (GCA) is inflammation of the lining of the arteries that run along the temple. GCA usually creates a headache that causes constant, throbbing pain in the temples.

Vision symptoms result from a loss of blood supply to the optic nerve and retina. Other symptoms include:

• Fever, fatigue, and muscle aches
• Scalp tenderness
• Pain while chewing
• Decreased vision​

Treatment may include:

• Corticosteroids
• Low dose aspirin
• Tocilizumab (monoclonal antibody that reduces inflammation)

Acute Angle-Closure Glaucoma 

Acute angle-closure glaucoma (AACG) is a rare type of glaucoma that causes symptoms like headaches to appear suddenly. Eye pressure rises quickly in AACG and causes:

• Increased eye redness
• Eye pain
• Cloudy vision
• Blurry vision

A mid-dilated pupil, in which the pupil dilates (widens) slowly and incompletely, is one of the most important diagnostic features of AACG.

Specific treatments depend on whether treating the condition acutely during the initial presentation or treating the condition chronically. Generally, acute and chronic AACG is treated through a combination of procedures, oral medications, and topical eye medications.

Ocular Ischemic Syndrome

Ocular ischemic syndrome is a condition that develops due to a chronic lack of blood flow to the eye. It is often indicative of atherosclerotic disease, and patients may have co-existing cardiac conditions. Sometimes, this condition is painless, and the most common reason patients seek care is decreased vision. This condition can cause additional signs and symptoms such as:

• Headache (related to eye pain, often lessens when lying down)
• Cataracts
• Glaucoma
• Iris neovascularization (the development of weak new blood vessels in the iris)
• Retinal hemorrhage (abnormal bleeding inside the retina, the tissue in the back of the eye)

White spots on the retina signal a lack of blood flow and oxygen to the retinal tissue.

Ocular ischemic syndrome can affect the entire body, and treatment often centers on an interdisciplinary approach with cardiologists, vascular surgeons, neurologists, and primary care. Additionally, treatment usually focuses on addressing complications from the disorder and may include a combination of procedures, topical eye medications, and oral eye medications.

Herpes Zoster

Herpes zoster is a reactivation of the chickenpox virus and is also commonly known as shingles. Before the painful blisters characteristic of the herpes zoster rash appear, patients may experience:

• Headache
• Light sensitivity
• Malaise

The rash typically appears along one or two dermatomes (neural pathways in the body) and heals over several weeks.

Complications of herpes zoster include:

• Clouding of the cornea, the clear outer layer of the eye
• Glaucoma
• Optic nerve atrophy (deterioration)

Treatment for shingles involves antiviral medication to lessen the duration of symptoms. The sooner medication is started after symptoms begin, the more effective it is. The rash is painful, so your healthcare provider may also prescribe pain medication depending on the severity of your symptoms.

Pseudotumor Cerebri

Pseudotumor cerebri occurs when cerebrospinal fluid (CSF) accumulates in the skull. Obesity, other health conditions, and some medications can contribute to the development of this condition.

Pseudotumor cerebri often causes headaches and changes in vision. There may be a pulsating sensation in the head, and nausea and vomiting may also be present. Left untreated, it can lead to vision loss because of pressure on the optic nerves.

Treatment aims to reduce fluid buildup and pressure. While the condition is often treatable, it may reoccur.

Carbon Monoxide Poisoning

One of the most common symptoms of carbon monoxide poisoning is a headache, which may include blurry vision if you continue to breathe in toxic amounts of carbon monoxide. Other common symptoms of carbon monoxide poisoning include:

• Dizziness
• Weakness
• Upset stomach
• Vomiting
• Chest pain
• Confusion

You may feel like you have suddenly developed the flu. Individuals who are sleeping or have had too much alcohol to drink may pass away before experiencing symptoms.

To prevent carbon monoxide poisoning, ensure a carbon monoxide detector is in your home and any rentals or hotels. Set reminders on your phone to check the batteries and change the detector per the manufacturer’s instructions.

Examples of appliances that can contribute to carbon monoxide poisoning that need to be appropriately maintained for safety include:

• Oil and gas appliances (e.g., furnaces)
• Chimneys
• Generators

Also, be aware of your garage ventilation when warming up or cooling down a car, as cars release carbon dioxide when running.

Additionally, avoid burning charcoal inside the home, using portable gas stoves indoors, and using generators indoors. These appliances should only be used outside—and in the case of generators, more than 20 feet from the home.

Carbon monoxide poisoning is treatable in a hospital with oxygen and other supportive measures depending on the severity of the poisoning.

Additional Causes of Blurry Vision and Headache

Vision problems can cause headaches when you either overwork the eyes or struggle to maintain focus, such as an eye strain headache. By correcting the vision problem, you can often resolve the headache.

Eye-Strain Headache

Vision problems can cause headaches when you either overwork the eyes or struggle to maintain focus, such as an eye strain headache. By correcting the vision problem, you can often resolve the headache.

Overusing the focusing muscles of your eyes can cause eye strain and headaches. An eye strain headache usually lasts up to an hour after extensive screen time, but it can last longer.

Common causes of eye strain include looking at screens for a long time, such as:

• Computer or laptop screens
• Cell phones
• TV screens
• Video games
• Other digital devices

The words and images on a screen are made up of pixels, which don’t have well-defined edges, so the eyes can’t easily focus on them.

As a result, the eyes must work harder, even if an image is high-resolution. When the eye muscles tire, a headache can develop around or behind the eyes.

Common symptoms of eye strain include:

• Headaches
• Blurry vision
• Eye fatigue
• Dry eye
• Irritated, burning eyes
• Increased sensitivity to light
• Difficulty focusing

Resting your eyes from screens and utilizing over-the-counter pain medications can treat eye strain headaches.

However, if you must be in front of a computer daily, you can take steps to prevent and treat eye strain headaches by doing the following:

• Using artificial tears as needed
• Tilting your computer screen slightly down
• Ensuring your eyeglasses or contact prescription (if you use them) is up to date
• Avoiding lights that are too bright
• Using a special type of progressive lens called computer glasses
• Following the 20-20-20 rule (every 20 minutes, shift your eyes to something at least 20 feet away for 20 seconds)

Farsightedness

Adults and children with uncorrected farsightedness (hypermetropia) will often experience headaches, especially when reading. Other symptoms include eye strain and difficulty seeing things up close.

Treatment involves corrective glasses or contact lenses.

Presbyopia

Around the age of 40, some individuals may start to have difficulty focusing on nearby objects. Activities such as reading or threading a needle can become challenging because of blurry vision. This condition is known as presbyopia, affecting most individuals at some point.

Headaches develop as you try to compensate for the lack of focusing power.

Occupations requiring close-up work, exposure to sunlight for extended periods, and looking at faraway objects are the most common risk factors for presbyopia.

Treatment includes an eye exam and prescription eyeglasses to correct the presbyopia and reduce eye strain.

Dehydration

Dehydration can cause headaches, blurred vision, double vision, and tired and strained eyes because the eye is not properly lubricated.

Treatment includes drinking plenty of water to help hydrate your eyes and reduce eyestrain.

Summary

Migraines and cluster headaches are common causes of blurry vision with a headache. They go away once you no longer have the headache. Eye conditions or eye strain can also cause headaches.

In some cases, vision difficulties and a headache, particularly when the headache is severe, are signs of a medical emergency, such as a stroke, lack of blood flow to the eye, or increased skull pressure. So, if you are experiencing headaches and vision changes, especially if these symptoms are new, seek immediate medical care to ensure prompt treatment and improve prognosis.