Causes of Light Sensitivity
Eye Conditions
Medication
Migraines
General health conditions
Other general health conditions can also increase a person’s sensitivity to light. Examples include:
- Blepharospasm (muscle spasms in the eyelids)
- Progressive supranuclear palsy (PSP)
- Fibromyalgia
- Stroke
- Traumatic brain injury
Managing Light Sensitivity
The best way to manage light sensitivity and glare is to limit the amount of light entering your eyes. Wearing sunglasses or tinted eye shields is often the simplest way to achieve this goal. Selecting the right glasses for your specific use case and underlying issue is critical.
Select the right lens
Tinted lenses reduce the amount of light that enters your eyes which can help with light sensitivity. This reduction of light does not harm your eyes or make them lazy.
Tinted lenses come in a variety of colors and can be light or dark. Different colored tints limit different wavelengths of light from passing through them. Selecting the right color and opacity depends on your underlying condition and personal preference. It’s important to remember that as well as helping your light sensitivity, the lenses you choose need to allow enough light through them for you to be able to see the best you can.
Select the right frame type
Depending on the level of light sensitivity and scenario, selecting the type of frame will be a key to reduce the impact of light. Wearovers are larger than normal sunglasses and can also be worn over your everyday glasses. These can be helpful if you are very light sensitive but need to wear a glasses prescription to see more clearly.
Wraparound shades have a close-fitting style to keep light from entering around the frame, and this means they wouldn’t fit over your everyday glasses. However, it might be possible for your prescription to be included in a wrap-around frame.
Understanding Light Sensitivity
(Photophobia)
Good lighting can help you make the most of your sight, particularly if you have an eye condition that is affecting your vision. However, for some people, everyday lighting conditions can seem too bright, causing them discomfort and this can even affect their quality of vision. Light sensitivity, also known as photophobia, often affects people who have an underlying eye condition.
Light sensitivity is often worse when you have an eye condition. This might be because there is inflammation (swelling) affecting part of your eye. There are some eye conditions that cause your eye to adapt more slowly to changing light levels, and this can make you more light sensitive in these situations. Your eye condition may cause changes that mean light is scattered inside your eye instead of reaching the macula as it should. This light scatter causes glare which can increase your sensitivity to light. Glare is described in more detail later in this factsheet.
Almost any eye condition can cause some degree of light sensitivity. This may make you feel more sensitive to light most of the time or only in certain situations.
We need light to be able to see but many people with low vision need more light than usual to carry out certain tasks, such as reading. However, sometimes the lighting around us interferes with our vision. When lighting makes it uncomfortable for you to see or makes your vision worse, it’s known as glare.
Glare can be a problem if a light is too bright for you, it’s coming from the wrong source, or it isn’t in the right place.
There are two types of glare that can cause problems - discomfort glare and disability glare. For some people, both can be present at the same time in certain circumstances.
Discomfort glare occurs when a light source is too strong for your eyes. It may cause you to “screw up”, shade or even close your eyes because the light level makes you feel uncomfortable. When trying to see in these bright conditions, however, discomfort glare doesn’t usually make your vision less clear than it was before.
A good example of when we might experience discomfort glare is moving from a dark room into bright sunlight. As our eyes adjust to the brighter level of light, it can sometimes feel uncomfortable. Usually, within a few seconds, our eyes adapt to the new level of light, and our initial discomfort goes away. As we get older, our eyes naturally adapt more slowly to varying light levels, meaning it can take longer than it did before to make these adaptations. However, some eye conditions can affect the speed of these adaptations, leading to greater problems with discomfort glare in some situations.
Discomfort glare can also be reduced if the lighting around you closely matches the lighting of your task. For example, a computer screen will be more comfortable to look at if it is viewed in a room that is lit to around the same brightness as the screen. Viewing the same screen in a dark room will lead to greater levels of discomfort glare.
Disability glare occurs when a light source reduces how well you can see, and the brighter the light is, the more glare it can cause. Some eye conditions cause disability glare, not only in bright lighting, but with everyday lighting as well.
Disability glare doesn’t necessarily cause discomfort, but it can reduce how much detail you can see. This type of glare generally reduces contrast, so that objects aren’t as easy to see against their background. If glare is very intense it can greatly reduce your vision, causing “dazzle”.
Disability glare is worse when:
- there is a greater amount of light scatter. This may be caused by an eye condition or by other factors, such as a dirty car windscreen.
- the glare source is brighter than the surrounding light; for example, car headlights cause more glare at night than in the day.
- the glare source is more in your line of sight; for example, the sun causes greater disability glare when it is lower in the sky, such as at sunrise or sunset.
A common eye condition which causes disability glare is cataract. The clouding of the eye’s natural lens means that light passing through it is scattered inside the eye. For example, the glare from oncoming headlights when travelling at night, often makes it harder for a person with cataract to see.
It’s important to see an optometrist (optician) if you are sensitive to light, so they can examine your eyes. An optometrist will be able to check the health of your eyes and look for any underlying eye condition which could be causing your light sensitivity or issues with glare.
If you suddenly become sensitive to light or your light sensitivity worsens, you should have your eyes checked as soon as possible, as it can indicate that an eye condition has become worse or that a new condition has developed. Much less commonly, more severe light sensitivity that starts very quickly can be the first sign of a serious condition, such as meningitis. If you are in any doubt, it is always best to have any new symptoms checked by a doctor or optometrist.
Everyone experiences some degree of light sensitivity at times, especially in very bright, sunny conditions and this is normal. It’s also true that light sensitivity affects people to different extents; some people are naturally more sensitive to light than others. This might be related to their iris colour, as iris pigment helps to block excess light from entering the eye. This means someone with a lighter coloured iris, for example blue eyes, might be more sensitive to light than someone with a darker iris.
However, some people are more light sensitive without having any underlying medical cause, and typically, their light sensitivity will be longstanding. When someone is sensitive to light with no underlying cause, this can still be managed in the same ways as light sensitivity relating to an eye condition.
If your light sensitivity is being caused by an underlying eye condition, your symptoms can improve if the eye condition can be treated; for example, removing a cataract or treating inflammation.
Unfortunately, not all eye conditions can be treated, but there are still things that can help you cope better with any light sensitivity and glare they cause.