9 reasons why you're suddenly so sensitive to bright light, according to ophthalmologists
- If you're suddenly more sensitive to bright light, it could be due to an underlying condition.
- Migraines, dry eye, corneal scratches, pink eye, and certain medications can cause photophobia.
When your eyes are exposed to bright light, your pupils constrict to limit how much light enters your eyes.
In some cases, bright light can be too much for your eyes to handle, no matter how small your pupils get. That's why most people will squint when walking from a dark bedroom into a bright kitchen or exiting a movie theater on a sunny day.
But if you regularly experience extreme light sensitivity and eye discomfort, you may have photophobia, or photoallodynia, though this term is rarely used.
Contrary to what the name suggests, photophobia doesn't refer to a fear of light, says Dr. Bradley Katz, a neuro-ophthalmologist and CEO of Axon Optics. Rather, it's a medical symptom that can result from a wide range of conditions.
Although photophobia typically affects both eyes, Dr. Christopher Starr, an ophthalmologist at Weill Cornell Medicine and NewYork-Presbyterian, says some people only experience it in one eye.
1. Migraines
Migraine headaches are the most common neurological cause of photophobia — in fact, 80-90% of people with migraines experience this symptom.
This happens because a pathway connects your eyes to the parts of the brain active during a migraine attack. During a migraine, light can worsen the pain by activating nerve cells in this pathway.
Other migraine symptoms can include:
- Sensitivity to noise and smells
- Dizziness
- Blurred vision
- Nausea and vomiting
- Loss of appetite
- Sweating or chills
According to Katz, some people experience sensitivity to light as the first symptom of a migraine episode. Light can act as a trigger or worsen pain during a migraine, but you may also experience prolonged photophobia between migraine attacks.
Other types of headaches, like tension headaches and cluster headaches, can also cause light sensitivity.
2. Dry eye
Another common cause of photophobia is dry eye.
Dry eye happens when your tears evaporate too quickly or your tear glands don't make enough tears to keep your eyes moist.
Note: Symptoms of dry eye tend to get worse as you get older, due to normal changes in your tear contents and tear glands.
According to a 2017 study, roughly 75% of people with dry eye symptoms report having sensitivity to light, with 39% experiencing moderate or severe sensitivity.
Along with photophobia, dry eye may cause:
- Eye aching or fatigue
- Stinging or burning in the eyes
- Eye redness
- Watery eyes
- A sensation of having something in your eyes
Some medications that may cause dry eye, which can then lead to photophobia, include:
- Antihistamines
- Certain heart medications
- Some antibiotics
- Diuretics
- Birth control pills
- Ulcer medications
3. Acute uveitis
Photophobia may also develop as a symptom of acute uveitis, or inflammation of the uvea, Starr says. The uvea is the middle layer of the eye.
Uveitis is usually caused by infections or blunt trauma to the eye. Autoimmune diseases, such as psoriasis, reactive arthritis, and multiple sclerosis (MS), may also cause uveitis because autoimmune reactions can sometimes result in eye inflammation.
In addition to photophobia, acute uveitis may cause:
- Eye pain
- Eye redness
- Dark, floating spots
- Blurred vision
4. Traumatic brain injury
A traumatic brain injury (TBI) can bring on sudden photophobia, according to Katz. In fact, a 2017 study found that 50% of people with a TBI experience photophobia.
Traumatic brain injuries usually happen as a result of a car accident, fall, assault, or firearm-related suicide attempt.
Extreme light sensitivity may go away on its own as the injury heals, but it could also become a chronic symptom.
About half of the participants in the study mentioned above reported reduced light sensitivity after the first year following the injury. But 42% said this symptom remained the same, while 3% experienced an increase in light sensitivity.
5. Corneal abrasions
According to Starr, photophobia may also result from a scratch or other injury to the cornea, the transparent tissue that covers the front of the eye.
Other symptoms of corneal abrasions may include:
- Stinging, burning, or other pain in the eye
- Blurry vision
- Eye redness
- Puffy eyelids
- Increase in tearing, or watery eyes
- The sensation that something is in your eye
Corneal abrasions may be caused by anything from contact with makeup brushes to getting sand or other debris in your eye.
The risk of corneal injuries increases for:
- Auto workers
- Woodworkers
- Metal workers
- Landscapers
- People who participate in certain sports like hockey, lacrosse, and racquetball
Wearing safety glasses or other eye protection during these activities can help protect your eyes.
Note: Prolonged use of contact lenses or wearing damaged contact lenses can also increase your risk.
If you suspect you have a corneal abrasion, especially if you notice changes in your vision, contact your doctor immediately. You may need a prescription for antibiotic
ointment or drops to reduce the risk of infection. It's also best to avoid wearing contact lenses until your doctor gives you the OK.
6. Blepharospasm
This condition is marked by abnormally frequent blinking, eye twitching, and extreme light sensitivity
Research from 2017 suggests a vast majority of people with blepharospasm experience light sensitivity — and bright light was especially likely to provoke eye spasms. Researchers also found photophobia is one of the most common factors that can negatively impact blepharospasm patients' quality of daily life.
An older study co-authored by Katz revealed this connection goes both ways: light sensitivity can also trigger blepharospasm and make the spasms worse.
7. Prescription medications
Starr says some medications contain ingredients that may increase light sensitivity. Those medications include:
- Benzodiazepines, like Valium and Diazepam
- Barbiturates, like Amytal, Butisol, and Nembutal
- Haldol, an antipsychotic often used to treat schizophrenia
- Chloroquine, an anti-malaria and immunosuppressant drug
- Zoledronate, a medication used to treat osteoporosis and bone damage
Important: If you suspect one of your medications causes increased light sensitivity, talk to your doctor right away. It's important to keep taking your medication until your doctor lets you know it's OK to stop — stopping medications abruptly can have serious health consequences.
8. Glaucoma
Photophobia can also be a sign of glaucoma, a group of eye conditions that damage the optic nerve in the back of your eye. Most often, photophobia is associated with a type of glaucoma that can quickly lead to permanent vision damage.
Other symptoms of glaucoma may include:
- Excessive tearing
- Eye pain or pressure
- Blurry or narrowed vision, or blind spots
- Headaches
- Nausea
- Eye redness
- Seeing rainbow-colored halos around lights
You'll want to call your eye doctor immediately if you experience extreme light sensitivity along with dilated pupils, severe eye pain, and redness. If you can't get in touch with your eye doctor, it's a good idea to get immediate medical attention at an urgent care clinic or emergency room.
9. Pink eye
Conjunctivitis, commonly called "pink eye," refers to an inflammation of the conjunctiva, the mucous membrane that lines the inside of the eyelids and covers the surface of your eye.
It's often caused by viral or bacterial infections and allergic reactions and can affect one or both eyes.
Pink eye may cause light sensitivity, along with:
- Burning or itchy eyes
- Eye redness
- A gritty sensation in one or both eyes
- Swollen eyelids
- Blurry or hazy vision
- White, yellow, or green discharge from your eye that may crust over
Other risk factors
According to Katz, increased sensitivity to light can happen with the following conditions:
- Epilepsy
- Styes
- Cataracts
- Fibromyalgia and other functional pain disorders
- Meningococcal meningitis
- Chronic fatigue syndrome
- Inflammatory bowel disease (IBD) via uveitis, though this is rare
- Eye allergies
- Trachoma
- Sjögren's syndrome and other autoimmune disorders
- Corneal infections and malformations
- An injury to vision pathways in the brain
People with albinism as well as people with very light-colored eyes are more prone to photophobia because they have less pigment in the iris to filter out light, Katz says. You're also more likely to develop photophobia if you have larger pupils, Katz says, since they take more light in.
Preliminary studies also link photophobia to certain mental health conditions, including agoraphobia and panic disorder. This may be because, as a 2015 study found, anxiety can increase your chances of experiencing dry eye, a well-known cause of photophobia.
Insider's takeaway
Photophobia refers to an extreme sensitivity to light that can be caused by a wide variety of issues. Its causes range from neurological and ocular conditions to eye injuries and prescription medications.
Photophobia will typically resolve along with the underlying condition, according to Starr. For example, artificial tears may relieve photophobia triggered by dry eye, and photophobia associated with an eye injury will likely improve as the scratch, scrape, or cut heals.
In some cases, photophobia may suggest a more serious underlying condition, like glaucoma. So, if you regularly experience this symptom, you'll want to make an appointment with an eye doctor or other healthcare professional as soon as possible.