Almost everyone has experienced a headache, which is pain in part or all of the head. If a headache occurs with or causes blurred vision, it may be due to an underlying condition or medical emergency.
Causes of a headache and blurred vision will usually have additional symptoms. Some of these conditions can have serious complications, so people should not hesitate to see a doctor if they have severe symptoms.
This article will discuss five possible causes of a headache and blurred vision, as well as treatments and when to see a doctor.
A wide range of medical conditions can cause headaches, and dozens of conditions may cause blurred vision.
However, doctors associate far fewer conditions with both blurred vision and headache, especially when they occur at the same time.
Some of the possible conditions that can cause simultaneous headache and blurred vision include:
Roughly one-third of those people with migraine also experience visual disturbances, such as blurred vision.
Some of the other symptoms that doctors commonly associate with migraine include:
- sensitivity to light and sound
- nausea and vomiting
- blind spots
- tunnel vision
- zigzag lines that move across the field of vision and often shimmer
- partial or complete temporary loss of vision
- objects seeming closer or further away than they are
- seeing dots, stars, squiggles, or flashes of light
- seeing an aura of light around objects
Visual symptoms of migraine tend to last an hour or less. Most people experience the visual problems before the pain sets in, but they can also occur during the headache itself.
People can typically treat the symptoms of migraine with analgesics, such as ibuprofen and aspirin, or prescription medications, such as sumatriptan or ergotamine drugs.
The sooner someone takes these medications in the course of the migraine, the more effective they usually are.
Low blood sugar
Blood sugar levels naturally rise and fall throughout the day and in between meals.
Hypoglycemia can cause headaches and blurred vision when the brain is starved of glucose, which is its primary fuel source.
Other signs and symptoms of low blood sugar levels include:
- feeling anxious or nervous
- sweating, clamminess, and chills
- feeling shaky
- fast heartbeat
- dizziness or lightheadedness
- irritation or impatience
- pale skin
- clumsiness or coordination problems
- lack of energy
- numbness or tingling in the tongue, lips, or cheeks
If someone thinks their blood sugar levels are too low, they may want to consume something with sugar or carbs, such as fruit juice, and check their blood glucose levels if they have an underlying condition such as diabetes.
If blood glucose levels dip below 70 mg/dL, the American Diabetes Association suggest eating 15 grams (g) of carbs, waiting 15 minutes, then retesting glucose levels.
If blood glucose levels are still below 70 mg/dL, the individual can eat another 15-g serving of carbohydrates and repeat the process until levels stabilize.
Once blood glucose levels are back to 70 mg/dL, a person can eat a healthful meal to prevent glucose levels from dropping again.
People whose blood glucose levels go too low may receive a hormone called glucagon. People with conditions that can cause severe hypoglycemia, such as diabetes, may receive a glucagon kit to keep at home. A healthcare professional will teach them how and when to use the kit.
A stroke can occur when a blood clot blocks a vessel carrying blood to the brain. This is called an ischemic stroke. Less commonly, a stroke may happen when a blood vessel in the brain ruptures, which is called a hemorrhagic stroke.
Strokes are responsible for 1 out of every 20 deaths in the United States, or around 140,000 deaths, every year.
Strokes can cause blurred vision in one or both eyes and a sudden, severe headache.
Other symptoms often associated with strokes include sudden:
- numbness or weakness of the arm, face, or leg, especially on one side of the body
- difficulty speaking and understanding speech
- trouble walking, dizziness, and loss of coordination or balance
Without prompt treatment, strokes may cause life-threatening and permanently disabling complications. If a person thinks they or someone around them is having a stroke, they must call the emergency services immediately.
A doctor may give someone who has had an ischemic stroke medication to help break up a clot and improve blood flow to the brain. They may also need to perform surgery to remove the clot.
People who have had a hemorrhagic stroke may require surgery to stop the bleeding in their brain.
Recovery from a stroke can take a long time and will require several forms of therapy. After a stroke, many people also have to take medications to reduce their risk of having another stroke.
Traumatic brain injury
A traumatic brain injury (TBI) is an injury that interferes with normal brain functioning. A jolt, bump, hit, blow, or penetrating object cause most TBIs.
The specific symptoms of a TBI depend on the part of the brain that the injury has affected and the extent of the damage. Although some signs of TBI can show up immediately, others can take days to weeks to appear.
A concussion is one type of TBI that occurs as a result of a blow to the head.
People with mild TBI often experience a headache and blurred vision. Other common signs of mild TBI include:
- dizziness and lightheadedness
- ringing in the ears
- a bad taste in the mouth
- changes in mood or behavior
- sensitivity to light or sound
- loss of consciousness for a few seconds to minutes
- trouble with attention, thinking, memory, or concentration
- a change in sleep habits
- nausea and vomiting
People with moderate to severe TBI often experience a headache that continues to worsen and persist. Other signs of a moderate to severe TBI include:
- slurred speech
- convulsions or seizures
- inability to wake up
- loss of coordination
- loss of consciousness, lasting minutes to hours
- persistent vomiting and nausea
- numbness or tingling in the arms or legs
- increasing confusion, agitation, or restlessness
Severe TBI can be life-threatening without treatment. The treatment for TBI depends on the extent, location, and severity of the injury.
Mild traumatic brain injuries, such as concussions, may only require monitoring and self-care.
People with mild TBI should temporarily limit doing certain activities that can stress the brain or increase the risk of reinjury, such as computer work or playing sport.
People with moderate to severe TBI need emergency care and may require surgery to prevent further damage to their brain tissues.
Carbon monoxide poisoning
Carbon monoxide is an odorless, colorless, tasteless gas present in the fumes that burning fuel creates.
More than 20,000 people in the U.S. are admitted to the emergency department for accidental exposure to carbon monoxide every year.
When people breathe in carbon monoxide, it binds to hemoglobin, which is the red protein in blood that carries oxygen around the body. When hemoglobin is bound to carbon monoxide, it cannot carry oxygen to organs and tissues.
Carbon monoxide poisoning causes a variety of symptoms as it deprives the body and brain of oxygen. A headache and vision problems, such as blurred vision, are common signs of carbon monoxide poisoning.
Additional symptoms of carbon monoxide poisoning include:
- upset stomach and vomiting
- chest pains
- flu-like symptoms
People with mild to moderate carbon monoxide poisoning should get themselves away from the poisonous gas and seek immediate medical treatment. A first responder can provide high-flow oxygen through a mask.
Emergency healthcare teams may give people with severe carbon monoxide poisoning 100 percent oxygen through a tube they put directly into the individual's airway.
People who think they have had a migraine headache for the first time should talk with their doctor. It is essential to identify and treat migraine soon after they occur. A person can also learn to recognize the warning signs and take medications quickly.
People can usually treat mild hypoglycemia by eating sugar or carbohydrates. Those experiencing signs of moderate to severe low blood sugar levels should seek emergency medical attention.
Anyone experiencing signs or symptoms of a stroke should seek emergency medical care to prevent serious complications, including disability and death.
The American Stroke Association encourage people to use the acronym FAST to decide when to call 9-1-1. FAST stands for:
- Face dropping
- Arm weakness
- Speech difficulty
- Time to call
Someone who shows signs of a mild TBI, such as headache and blurred vision, should talk with a doctor to confirm the diagnosis and learn how to take care of themselves in the days to weeks after the injury.
Someone experiencing signs of a moderate to severe TBI, such as a headache and blurred vision that continues to get worse, may need emergency medical care.
Anyone who thinks they have carbon monoxide poisoning, especially people with a headache and flu-like symptoms, should seek urgent care. If someone might have carbon monoxide poisoning but is unconscious, someone else must take them to a hospital or call 9-1-1.
Most people only have blurred vision and a headache for a relatively short time before making a full recovery. If a person has additional symptoms, they may require a doctor's care.
People with migraine tend to experience a headache and blurred vision at the same time for an hour or less, though the head pain can last for several hours.
People with mild hypoglycemia usually start feeling better shortly after raising their glucose levels back to normal.
However, people who experience blurred vision and headache because of severely or chronically low blood sugar levels, stroke, TBI, or carbon monoxide poisoning require emergency care.