Photophobia and Sensitivity to Light: Causes, Onset, and Treatments

Photophobia, or sensitivity to light, is a condition where exposure to light causes discomfort or pain in the eyes. The word comes from the Greek ‘photo’ meaning light and ‘phobia’ meaning fear, ‘fear of light’.

Photophobia can affect people differently, from a mild aversion to bright light to severe pain under normal lighting conditions. Very bright light leads to discomfort or pain under normal circumstances but photophobia is an abnormal sensitivity to light and is a frequently reported symptom which is often poorly understood.

Understanding what causes photophobia, why it might suddenly develop, and what treatments are available is essential for managing this condition effectively.

What Causes Photophobia?

Photophobia is not a condition itself but rather a symptom of an underlying issue. It can result from a wide range of causes, including:

1. Eye Conditions

Dry eyes: Insufficient tear production can lead to discomfort and heightened light sensitivity. More about dry eyes.

Dry eye conditions lead to irritation of the trigeminal nerve which provides the cornea with sensation so that even after signs of dry eye are improved with treatment, long term irritation and therefore photophobia can still be present.

Corneal abrasions: Scratches or mild trauma to the cornea will make the eyes immediately more sensitive to light.

Glaucoma: A sudden increase in pressure of the eye can make light sensitivity more pronounced. This is the case in acute glaucoma.  More about Glaucoma.

Uveitis: Inflammation in the uvea (the eye’s middle layer) is a common cause of photophobia. This can affect the front part of the uvea or iris, called iritis, or the uvea further back when it is called uveitis.

Cataracts: Clouding of the lens will scatter light entering the eye, leading to discomfort. This may be more noticeable under certain conditions e.g. low light or twilight and a bright source of light e.g. driving at night when drivers with cataract will experience uncomfortable glare. More about cataracts.

Corneal scars: These can result from infections, recurring infections e.g. herpes simplex virus or trauma and result in a focal loss of clarity of the cornea which then scatters light.

Lack of protective pigment: A lack of pigment in the eye, either in the iris or the retina leaves the eye unprotected from even normal or low levels of light and photophobia can be severe.

Conditions that affect the front, uveal coat of the eye include trauma or inherited conditions e.g. albinism or ocular albinism. Condition that affect the coats of the retina include retinitis pigmentosa.

In general, anything that causes inflammation or injury to the eye will result in light sensitivity and these tend to be conditions that require urgent attention.

Conditions that cause light to scatter e.g. cataracts or corneal scars will also cause photophobia, but these tend to be chronic, and although they can be just as important, tend to be less urgent.

2. Neurological Conditions

Migraine: Light sensitivity is a hallmark symptom of migraines, often accompanying throbbing headaches, nausea, and visual disturbances. Most migraine sufferers experience photophobia before developing a headache and as a separate symptom from the visual aura, typically zig zag lines, that also tend to occur before the beginning of headache.

Traumatic brain injury (TBI): A concussion or head injury can disrupt normal brain processing, including the way it handles light.

Brain haemorrhages: or bleeds, rarely brain tumours can cause photophobia

Meningitis: Inflammation of the membranes surrounding the brain and spinal cord can cause severe light sensitivity.

Optic neuritis: Anatomically, the eye is part of the brain, so that any condition that causes inflammation of the membranes around the brain or optic nerve can cause photophobia. Several conditions can cause optic neuritis including multiple sclerosis, where the fatty sheath that surrounds the optic nerve becomes inflamed and then lost, leading to loss of vision.

3. Medications

Many eyedrops themselves can cause irritation of the cornea which in turn can lead to photophobia but more frequently, it is the preservatives in eyedrops that are the culprit, the most frequent offender being benzalkonium chloride (BAK).

Systemic medications e.g. barbiturates and drugs to control mood or relieve anxiety e.g. benzodiazepines can also result in photophobia.

4. Psychiatric disorders

Certain psychiatric disorders including agoraphobia (fear of open spaces or being outdoors) or anxiety states can also be associated with photophobia.

Why Might Photophobia Start Suddenly?

The sudden onset of photophobia can be alarming and acute causes include :

Infections: Rapidly developing infections, such as conjunctivitis, keratitis, or sinusitis, can trigger light sensitivity.

Injuries: Trauma to the eye or head, including corneal scratches or concussions, can cause immediate discomfort under light.

Neurological events: A sudden migraine, or worsening of a pre-existing condition like glaucoma may present with photophobia.

In some cases, no clear cause is identified, and the sensitivity may develop gradually due to cumulative eye strain, prolonged screen use, or changes in general health.

Solutions and Treatments for Photophobia

The treatment of photophobia depends on its underlying cause. Addressing the root issue is key to managing symptoms effectively.

As some cases of acute photophobia can be extremely serious, it is important to seek immediate medical attention if the cause is not immediately known.

The symptoms of photophobia can be helped by these common solutions:

1. Eye Protection

Sunglasses: High-quality sunglasses with polarised lenses can reduce glare and UV exposure.

Specialised filters: Glasses with FL-41 tinted lenses are designed to block specific wavelengths of light that can trigger discomfort, especially for migraine sufferers.

Adjust lighting: Use soft, natural lighting and avoid harsh fluorescent lights.

2. Management of the Underlying Condition

Dry eye treatment: Use artificial tears, lubricating ointments, or prescription eye drops to manage dryness. Avoiding preservatives in eyedrops can make a significant difference, particularly if the drops are to be used for the long term.

Migraine management: Medications, lifestyle changes, and avoiding triggers can help reduce light sensitivity associated with migraines.

Infection care: Antibiotics, antivirals, or antifungal treatments may be prescribed for eye infections.

3. Neurological Therapies

Addressing photophobia linked to brain injuries or neurological conditions will require specialist medical treatment.

4. Lifestyle Adjustments

Minimise screen time: Use blue light filters on devices and take regular breaks during prolonged screen use.

Stay hydrated: Dehydration can exacerbate symptoms.

Eye hygiene: Avoid rubbing your eyes and ensure good cleanliness to prevent infections.

5. Seek professional Help

See an optometrist or ophthalmologist for persistent or severe symptoms.

A neurologist may be consulted for migraines, brain injuries, or unexplained photophobia.

When to Seek Immediate Medical Attention

Seek prompt medical help if photophobia is accompanied by any of the following:

• Sudden or severe pain in the eye.
• Blurred or reduced vision.
• Nausea, fever, or a stiff neck (possible signs of meningitis).
• Loss of consciousness.
• Recent head injury or trauma.

Conclusion

Photophobia can significantly impact daily life, but with proper management and treatment, the effects can be minimised.

Understanding the potential causes, especially if symptoms appear suddenly, is the first step in addressing the issue.

Whether the solution involves lifestyle changes, protective eyewear, or medical treatment, seeking advice from a healthcare professional ensures that any underlying conditions are properly diagnosed and treated.