Light sensitivity (photophobia): causes, red flags and when to get help

Light sensitivity means that normal levels of light feel uncomfortable, painful or glaring, and that you may want to close your eyes, wear sunglasses indoors or avoid bright rooms. The medical term is photophobia, although it has nothing to do with being afraid of light. It is a symptom that can arise from the eye itself, from the brain and nervous system, or from illness elsewhere in the body.

Because the underlying cause varies so much, the useful questions are what else is happening and how fast it started. A long-standing, mild sensitivity that comes with headaches is a very different situation from sudden painful, red eyes or sensitivity together with fever and a stiff neck.

The NHS describes migraine as a condition that causes symptoms such as a severe headache, feeling sick and sensitivity to light. Its list of main symptoms includes a throbbing headache, often on one side, nausea or vomiting, and being very sensitive to light and sounds.

Some people also have aura, such as seeing zigzag lines or flashing lights, numbness or tingling, dizziness or difficulty speaking, which the NHS says should not last longer than 1 hour. For many people with migraine, resting in a quiet, dark room is the practical way to cope with the sensitivity during an attack.

The NHS advises seeing a GP if attacks are severe or getting worse, last longer than usual, happen more than once a week or are hard to control. It advises asking for an urgent appointment or contacting NHS 111 if an attack has lasted longer than 72 hours, aura symptoms last longer than 1 hour at a time, or you are pregnant or have just had a baby.

Several common eye problems include light sensitivity among their symptoms.

• Dry eyes: the NHS lists eyes that are itchy, sore, gritty, red, blurry, sensitive to light or more watery than normal, caused by not making enough tears or tears that dry up quickly.

• Uveitis (also called iritis): inflammation inside part of the eye. The NHS lists eye pain that may feel worse when reading, red or watery eyes, reduced or blurred vision, sensitivity to light, and flashes or floaters. It usually affects one eye and symptoms can develop quickly or gradually.

• Conjunctivitis: the NHS says pain in the eyes, sensitivity to light, changes in vision or very red eyes can be signs of a more serious eye problem and need an urgent GP appointment or NHS 111.

• Other conditions that the NHS says cause symptoms similar to uveitis include glaucoma, keratitis, scleritis and an eye injury.

The NHS gives clear thresholds. For uveitis and conjunctivitis it says to ask for an urgent GP appointment or get help from NHS 111 if you have pain in your eyes, sensitivity to light, changes in your vision such as flashing or blurring, or very red eyes in one or both eyes. For uveitis it says to go to A&E or call 999 if you cannot see.

For dry eyes the NHS goes further: call 999 or go to A&E if you have any changes to your sight like wavy lines, flashing or loss of vision, if it hurts to look at light, if you have a red eye with severe headache and feel sick, if your eye or eyes are very dark red, or if you have injured or pierced your eye or something is stuck in it.

Meningitis is rare but serious. The NHS lists a high temperature, very cold hands and feet, a stiff neck, joint and muscle pain, a severe headache that is getting worse, eye pain when looking at bright lights, seizures, vomiting, confusion, being very sleepy and a rash that does not fade when pressed with a glass. It says to call 999 or go to A&E if an adult or child aged 5 or over has a very painful headache, is confused, has a stiff neck and cannot look at bright lights, has a rash that does not fade, or has a first seizure.

A GP will ask when the sensitivity began, which eye or eyes are involved, whether there is pain, redness, headache or fever, what medicines you take and whether you wear contact lenses. They may examine your eyes, check for signs of infection or inflammation, and refer you on. For suspected uveitis the NHS says a GP will refer you to an eye specialist (ophthalmologist) and you will usually be seen within 24 hours so treatment can start quickly.

Where the cause is a migraine, assessment relies mainly on your description of attacks. If symptoms suggest meningitis or another serious illness, the priority is emergency assessment and treatment rather than outpatient tests.

There is no single treatment for light sensitivity because the cause drives the approach. For uveitis, the NHS says you will usually be prescribed a combination of medicines to get rid of any infection, reduce inflammation and relax the eye and reduce pain, and that severe or recurrent cases may be offered immunosuppressants, laser phototherapy, cryotherapy or surgery. After starting treatment you will be seen again by an ophthalmologist to check how it is working and for complications such as vision loss.

For migraine, the NHS describes treatments to ease attacks and treatments to prevent them, including medicines such as beta blockers, antidepressants and epilepsy medicines, acupuncture, relaxation techniques and cognitive behavioural therapy, and says a GP may recommend lifestyle changes such as eating at regular times and drinking less caffeine. Dry eyes are managed according to the NHS advice for that condition.

If sensitivity is long-standing and the cause has been assessed, practical steps include wearing a hat or sunglasses outdoors, adjusting screen brightness, and asking for lighting changes at work. Keeping a diary of when it occurs can help you and your clinician spot patterns such as links with migraine attacks or screen use.

Do not self-treat a painful, red or visually blurred eye with leftover drops; the right drops depend on the cause and some can do harm if the problem is inflammation or infection.