13 Causes of Blurry Vision and Headache

Blurry vision and headaches can occur together with migraine headaches or may be a sign that your eyes are overtaxed or that they are changing. It could also indicate a health issue or emergency condition that isn't specific to your eyes at all.

Common causes of blurry vision and headache include:

• Migraines
• Eyestrain
• Uncorrected farsightedness
• Presbyopia (difficulty focusing on nearby objects)
• Stroke
• Hypoglycemia (low blood sugar)
• Traumatic brain injury

This article will discuss how different kinds of headaches can affect your eyes and vision and when your symptoms may be a sign of a medical emergency that needs prompt care.

Headaches That Cause Blurry Vision or 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 often arrives before the actual headache. The aura 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 all trigger a migraine headache.

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:

• Eye tearing (tears in eyes)
• Nasal drainage
• Red eyes
• Eyelid droop
• Changes in pupil size

Cluster headaches may occur daily for several months at a time. This is followed by a long period with no headaches.

The exact cause of cluster headaches is unknown.

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 within an hour is crucial to improve prognosis and help reduce disability.

The warning signs of 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 loss of left-sided vision, whereas damage to the left side of the brain causes right-sided vision loss.

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.

Head Trauma

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

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 occur as a result of 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​

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.

Ocular Ischemic Syndrome

Ocular ischemic syndrome is a condition that develops due to a chronic lack of blood flow to the eye. This condition often causes symptoms such as:

• Headache
• Decreased vision
• 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.

Herpes Zoster

Herpes zoster (shingles) causes headaches, vision changes, and severe pain around the head and eye.

Herpes zoster is a reactivation of the chickenpox virus. It affects a single side of the body. A headache usually comes before an outbreak of painful skin blisters.

Complications of herpes zoster include:

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

Pseudotumor Cerebri

Pseudotumor cerebri is a condition that occurs when the pressure within the skull increases for no apparent reason.

Pseudotumor cerebri is also referred to as idiopathic intracranial hypertension. "Idiopathic" means the cause isn't known, and "hypertension" is high blood pressure.

Pseudotumor cerebri often causes a headache and changes in vision. If left untreated, pseudotumor cerebri can lead to vision loss. This is because the pressure places strain on the optic nerves.

Fortunately, while 65% to 85% of people with pseudotumor cerebri will experience visual impairment, the condition is usually temporary. It will return to normal when the hypertension is controlled.

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 for up to an hour after extensive screen time. Sometimes it can last longer, though.

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 and don't have well-defined edges. The eyes can't easily focus on pixels.

As a result, eyes must work harder, even if an image is in high resolution. When the eye muscles get tired, 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
  

Farsightedness

Adults and children with uncorrected farsightedness (hypermetropia) will often experience a frontal headache (also known as a brow ache).

If you are farsighted, you may find it difficult to focus on nearby objects. This results in eye strain and headaches.

As you subconsciously compensate for your farsightedness by focusing harder, the headaches can become worse and more frequent.

Presbyopia

Around the age of 40, people start to have difficulty focusing on nearby objects.

Activities such as reading or threading a needle are often difficult to perform because of blurry eyes. This is an unavoidable condition known as presbyopia that affects everyone at some point.

Headaches develop as you try to compensate for the lack of focusing power. Reading glasses can often relieve the underlying eye strain.

Occupations that require close-up work, exposure to sunlight for longer periods of time, and farsightedness are the most common risk factors for presbyopia.

Dehydration

Dehydration can cause headaches and blurred vision in addition to double vision and overall tired and strained eyes because the eye is not properly lubricated. Drinking plenty of water will serve to flush salt out of the body and hydrate your eyes to help reduce eyestrain.

Summary

Headaches may be a sign that there is a problem with your vision. For example, migraines and cluster headaches may temporarily cause vision symptoms. But these issues go away once you no longer have the headache. Eye conditions or eye strain can also cause headaches.

In some cases, vision difficulties along with a headache, particularly when the headache is severe, can be signs of a medical emergency, such as a stroke, lack of blood flow to the eye, or an increase in skull pressure. For this reason, if you are experiencing headaches and/or vision changes, always seek urgent medical care to ensure prompt treatment and improve prognosis.