Understanding Photophobia

Photophobia is a sensitivity to light. You may experience a sensitivity to very bright light, such as sunlight, or low light, such as incandescent lighting. Depending on the severity of your sensitivity, you can have a little discomfort or experience bad eye pain.

Those with light coloured eyes (e.g. light blue) can be more likely to have problem with light sensitivity, however photophobia is also caused by a range of eye conditions, as well as conditions that affect the entire body.

Types of Light

Photophobia can result in sensitivity to a range of different light sources – one, some, or all may cause you problems. These light sources can include:

-    Sunlight
-    Reflective surfaces, such as roads or windows
-    Water glare
-    Reflection from sand or snow
-    Artificial light sources (fluorescent or incandescent lights)

Signs & Symptoms

There are a few signs and symptoms that can let you know you are experiencing photophobia, these can include:

• Squinting
• Feeling like you need to close your eyes
• Headaches 
• General discomfort around light
• Severe eye pain in light, even indoors
• Red eye or blurred vision with light sensitivity

Some of these symptoms may go away after a day or two, however, if you are concerned, or symptoms persist, visit your optometrist or health care provider.

What Causes Photophobia?

Photophobia is usually caused by an underlying eye condition or problem that results in light sensitivity. However, there is spectrum of sensitivity and you may be sensitive to light without any physical cause, or as a side effect from growing older. It is still important that you visit an optometrist (optician) if you are experiencing photophobia, so they can rule out the possible causes. 
A few common causes can include:

• Migraine headaches
• Acute iritis or uveitis (internal eye inflammation)
• Corneal abrasion
• Corneal ulcer
• Contact lens irritation
• Glaucoma
• Conjunctivitis 
• Eye disease or infection
• Eye injury
• Meningitis, or another central nervous system disorder
• Detached retina

Some of these causes, such as meningitis or corneal abrasion, are considered medical emergencies and urgent care may be required. 

How Your Eye Works: The Basics

There are four main components that help the eye function: 

The Cornea and Lens are found at the front of the eye, and focus light coming into the eye. This allows you to form an image on the retina. 
The Retina is at the back of the eye. It is a layer of tissue that senses light and colour, converting them into electrical signals.
The Optic Nerve transmits electrical signals from the retina to the brain for interpretation. This lets us understand the information sent through from the eye.

If there is a problem with one of these components, the control on the amount or quality of the light entering the eye is compromised, resulting in light sensitivity. 

How is Photophobia Diagnosed? 

To diagnose the source of your photophobia, you will need to get an eye test at your local opticians. 

Eye Test

During your visit, the optometrist will most likely do the following things:

Ask about Family History & Current Symptoms

Your optometrist will usually start by asking about your family history of conditions and ask about your symptoms. They will talk to you about various different things to do with your light sensitivity (like if it is accompanied by a headache, how often you experience it etc.), as well as if you are experiencing additional symptoms, such as blurry vision. They may also ask about your health, lifestyle, and medication.

Your medical history, symptoms, or age may result in a few further tests being run, such as checking for glaucoma or diabetic retinopathy.

Conduct an Eye Exam

You will have your eye examined to check for any underlying problems, this will involve an Ophthalmoscope exam, where light shines into your pupil to check the inside of your eye, as well as your pupil’s reflexes. You will also have your eye movements and co-ordination (to ensure your eyes are synchronised) checked.

Run Tests

There are a range of tests that may be run, some of these can include: 

Visual acuity test – using a Snellen chart (each row of letters decreases in size) you can be asked to read through different lenses.

Visual field Screener – dots of light flash on a black background, if you can’t see any dots it can indicate a blind spot.

Focus test – tests your ability to focus at different distances.

Non- contact tonometer - blows puffs of air into the eye to check pressure (high pressure can indicate glaucoma).

Slit lamp – examines the cornea, iris and the lens for abnormalities.

How do you treat Photophobia? 

The course of treatment will very much depend on the underlying cause. If the condition causing the problem (e.g. cataracts or uveitis) is treated, you should see an improvement in your light sensitivity. If you are someone whose eyes are naturally light sensitive, an optometrist can advise on glasses to help reduce the discomfort or pain. 

Glasses

Anti-glare Lenses

Anti-glare lenses help reduce the glare from reflective surfaces, such as windows, water, the road, snow, and sand.

Anti-UV Lenses

Glasses or Sunglasses should have UV filters to help protect your eyes from harmful sun rays. It is best to have UV lenses that protect from both UVA and UVB light. 

Polarised Sunglasses

Polarised lenses are useful in very bright sunlight as they can help reduce the glare reflected from flat surfaces like water, snow, sand, windows, or car bonnets. 

Tinted Lenses

Tinted lenses can range from blues to reds and yellows, all limiting certain light wavelengths from entering the eyes and causing discomfort. The colour of the tint you choose tends to be more a matter of personal preference. It is not the case that certain tints help certain situations, rather that particular tints will ease a problem for a particular individual. 

Your optometrist can discuss the different tints with you, and which might be best for you. They may offer you different tints to test for a period of time, or use a MRC Intuitive Colorimeter to determine the colour filter best for you (it’s different for each person). However, the latter is usually only used for those with migraine, epilepsy or reading problems (i.e. dyslexia), as general colours may not help them.