Why bright light can cause a headache

The brain and eyes share pathways that can become unusually sensitive during a migraine. Glare, flickering light and a bright screen may then increase head pain or nausea. Long periods of close screen work, dry eyes or an outdated prescription can cause eye fatigue. Nasal congestion from allergic rhinitis, a cold or chronic sinusitis may create pressure around the face. Fever, fluid loss and heat exhaustion can also make a headache feel worse. The trigger alone does not identify the cause, so the timing and accompanying symptoms matter.

Step away from glare and rest in a gently lit, cool room. Lower screen brightness, increase text size and use regular distance breaks. Drink fluids, eat at your usual times and avoid intense heat while symptoms settle. Sunglasses outdoors may help briefly, but wearing very dark lenses indoors can make light tolerance poorer for some people. Record the light source, duration, pain location, sleep, food, fluids and other symptoms. Follow the label for any pain medicine and seek advice if you need it often.

Seek emergency help for a sudden explosive headache, new weakness or numbness, trouble speaking, confusion, collapse, seizure, stiff neck or a new loss of vision. Get prompt advice when headache follows significant heat exposure, severe vomiting or inability to keep fluids down. Book an assessment if the problem is new, recurring, steadily worsening or affecting your normal activities.

Could this be migraine, eye strain, sinus pressure or another problem? Should my eyes or medicines be reviewed? How can I manage the first symptoms? What changes would make this urgent?