What should you know about dehydration and light sensitivity?

Light sensitivity means ordinary light feels uncomfortable or painful. Dehydration can occur with thirst, dry mouth, dark urine, weakness or headache, and headache can make light harder to tolerate. Migraine commonly presents with light sensitivity, while conjunctivitis may cause eye redness or discharge. Meningitis can present with severe headache, fever, neck stiffness and light sensitivity; that combination needs urgent care.

Rest in a comfortably dim room, reduce screen glare and sip fluids if you may be dehydrated. Avoid driving if vision is affected. Do not use someone else’s eye drops. Note when the sensitivity began, whether one or both eyes are affected, and any headache, fever, rash, redness or discharge.

Seek emergency help for light sensitivity with fever, neck stiffness, confusion, a sudden severe headache, weakness, fainting or a new rash. Arrange prompt eye or medical assessment for severe eye pain, vision loss, marked redness, injury, or symptoms that persist despite rest and fluids.

Ask whether the pattern fits Migraine, an eye condition or another cause. Tell the clinician about hydration, headache history, medicines, contact-lens use, fever and changes in vision.