Photophobia, or photosensitivity, is eye pain, discomfort, and light sensitivity. It can be caused by a light source such as sunlight, incandescent light, or fluorescent light. Light sensitivity is a common complaint among people living with various neurological disorders. According to experts, it is a frequently reported symptom of migraine and many other neurovisual disorders.

Sensitivity to bright light can also be a distinguishing characteristic of eye conditions associated with multiple sclerosis (MS), including:

• Optic neuritis — Damage and inflammation of the optic nerve
• Uveitis — Inflammation of the uvea

“I started developing sensitivity to light after my MS diagnosis. I have severe light sensitivity in all light settings,” one MyMSTeam member shared.

What Does Light Sensitivity in MS Feel Like?

People with MS sometimes report abnormal and extreme sensitivity to natural light and artificial light followed by eye pain, eye strain, or eye irritation. “Lately, I have been sensitive to house lights, car lights, and the television. It’s like my eyes are always tired, and I have to close them to feel better,” one MyMSTeam member described. “I have the same problem,” another replied. “Daylight hurts and irritates my eyes.”

Some members reported feeling confused and disoriented when faced with too much light. “If I am in a room with bright light or glare, I start to feel a bit vague and then become confused,” one member shared with others. “I forget names and have to ask my partner. Sometimes, it takes me a bit longer to say things out loud.”

Other members mentioned that light sensitivity affects their daily lives. “The bright lights in my office bother me so much,” one member shared. Another replied, “I also have problems driving at night because the lights on the cars bother my eyes.”

How Common Is Light Sensitivity in MS?

Vision problems are often the first symptom of MS to appear. Photophobia is a symptom caused by an underlying condition. Currently, there is no research specifically on the prevalence of photophobia in people with MS. However, there are numerous studies on vision problems associated with MS that share the symptom of photophobia.

According to this recent study, uveitis is found to be 10 times greater in people living with MS compared to the general population. Another study found that half of the people diagnosed with optic neuritis had a 15-year risk of developing MS.

In addition, headaches are a frequently reported symptom in people living with MS. Photophobia is a common symptom associated with headaches, specifically migraine headaches. A study found that about 57.7 percent of people with MS experience headaches, of which 25 percent had migraines and 31.9 percent had tension-type headaches. A tension-type headache is a mild to moderate headache that feels like a tight band is wrapped around the head.

What Causes Light Sensitivity in MS?

MS affects the nervous system by attacking the myelin that protects the nerve fibers throughout the central nervous system, which includes the brain, brain stem, spinal cord, and optic nerve. The process of demyelination results in lesions (scarring) throughout the central nervous system that disrupt messages between the brain and the body.

The retina is a light-sensitive layer of tissue at the back of the eye. In the topmost layer of the retina, there are neurons called retinal ganglion cells. The axons of these cells make up the nerve fibers of the optic nerve. Retinal ganglion cells help to carry the light information from the retina and transmit it into a signal through the optic nerve to the brain.

Although the underlying mechanism and cause of photophobia remain unclear, experts have proposed a few plausible explanations for why people with MS have a lower tolerance to light. Scientists believe that demyelination can cause structural nerve damage and abnormal transmission of the neural pathways between the retinal layer, the optic nerve, and the brain stem.

Other scientists suggest that photophobia in MS may be caused by an increase in nerve impulses in the trigeminal pain neural pathways. The trigeminal nerve — one of 12 pairs of nerves attached to the brain — is responsible for sensations (pain, touch, and temperature) from the face to the brain. It also contains the ophthalmic nerve, which supplies the nerves with sensory information from the eyes, upper eyelids, and forehead.

The Migraine Connection

Studies have found that people with MS have a high prevalence of headaches — an ongoing symptom in about 27 percent. More than half (57.7 percent) report having at least one headache in their lifetime. Around 4 out of 5 people living with migraine also have photophobia.

Common triggers for both MS flare-ups and migraine attacks include:

• Stress
• Fatigue
• Lack of sleep or quality of sleep
• Poor diet
• Changes in weather
• Drugs and alcohol
• Infection

More than 22,849 members of MyMSTeam report experiencing headaches, including migraine headaches. “Too much sunlight will trigger a migraine,” one MyMSTeam member explained. “So whenever I go outside, I wear sunglasses.”

Medications

In various studies, disease-modifying therapies (DMTs) have been proven to slow progression and reduce the rate of relapses in MS. One study reported that the DMT interferon-beta — sold under brand names including Avonex and Betaseron — has a side effect that increases the risk of headache onset or worsening of old headaches in people with MS. Natalizumab (Tysabri) and fingolimod (Gilenya) have also been associated with headaches as a side effect.

Other common drugs and medications that may cause photophobia include:

• Antihistamines (used to control allergy symptoms)
• Amphetamines (used for attention disorders and narcolepsy)
• Phenylephrine, an ingredient in some cold and flu medications
• Scopolamine (used to prevent nausea)
• Trifluridine (prescribed for viral eye infections)
• Certain antidepressants

Other Causes

Other neurological conditions — including meningitis and traumatic brain injury — can cause photophobia. Other eye conditions, such as chronic dry eye, cataracts, eye infections, and eye allergies, can cause photophobia. You may also experience it when recovering from eye surgery.

People with light-colored eyes (blue, green, or gray) are more sensitive to light compared to those with dark-colored eyes, such as brown. This is because lighter-colored eyes have less pigmentation to also protect the retina from the sun and other light sources. The more light that passes through the eyes, the more nerve cells in the eye are stimulated.

Managing Light Sensitivity in MS

Because photophobia is a symptom of an underlying medical condition, it is important to keep your MS and other medical conditions well-managed. Speak with your health care provider to determine the exact cause of your light sensitivity.

Certain lifestyle changes can make photophobia easier to manage. Ophthalmologists recommend those with photophobia wear sunglasses that block out blue and green wavelengths. Polarized sunglasses with ultraviolet (UV) protection are a great option and can be found at your local optical shop. Rose-colored sunglasses can also help block out blue and green wavelengths and may be a more affordable option.

“My doctor told me I do not have optic neuritis but suggested I wear indoor and outdoor glasses that can block out the blue color in light,” wrote one member. “Wearing sunglasses with UVA and UVB protection has also helped me,” said another.

You can also ease photophobia at home by avoiding direct sunlight, closing your eyes during bright flashes of light, wearing dark glasses, and darkening the room.

Seek immediate medical care if your pain feels moderate or severe even in low-light settings, or if you begin to experience headaches, eye redness, blurred vision, or loss of vision.

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Have you experienced photophobia with MS? Share your experiences in the comments below or by posting on MyMSTeam.