Headache behind one eye: causes, red flags and when to get it checked

Pain behind one eye usually comes from the nerves and blood vessels around the head rather than from the eye itself. The pattern, how long each episode lasts, and what happens in the eye or nose during an attack tell a clinician most of what they need to know.

The list below goes from the more usual benign causes to the rarer ones.

• Migraine: throbbing pain, often one-sided, with nausea, light or sound sensitivity, sometimes preceded by visual aura. It builds over an hour or so and settles with rest in the dark.

• Tension-type headache: a pressing band or ache that can feel centred behind the eyes, usually both sides but occasionally one, without nausea.

• Cluster headache: severe, stabbing pain around or behind one eye, with a watering, red eye, a drooping eyelid or a blocked nostril on the same side. Restlessness during attacks is typical, and it is more common in men.

• Sinusitis: pressure behind the eye and cheek with a blocked or discoloured nasal discharge, usually after a cold. True sinusitis is over-diagnosed in people with migraine.

• Eye strain and uncorrected vision: a dull ache after screen work or reading that eases when the eyes rest.

• Optic neuritis: pain on moving the eye with dimmed colour vision in younger adults, sometimes the first sign of demyelinating disease.

• Acute angle-closure glaucoma and giant cell arteritis: uncommon but sight-threatening, and the reason a sudden severe eye-area headache is treated seriously.

Pain that is new and severe, comes with any loss or blurring of vision, a fixed pupil, a red eye, vomiting, or follows a head injury deserves prompt examination. So does a first-ever headache after the age of 50, especially if the scalp is tender to the touch or the jaw aches while chewing.

Choose the level of urgency that matches the features you have.

• Call 999 or go to A&E: sudden severe headache that peaks within a minute, headache with weakness, slurred speech or facial droop, or sudden loss of vision.

• Go to A&E or an emergency eye service today: a painful red eye with blurred vision, haloes or nausea.

• Call NHS 111 or see a GP the same day: new one-sided headache over 50 with scalp tenderness, jaw pain or vision disturbance; fever with stiff neck or rash.

• See a GP within days to weeks: repeated attacks, a pattern of the same-time-each-day pain, or headaches that are changing or worsening.

Expect questions about when attacks started, how long they last, whether the eye waters or the lid droops, any aura, triggers such as alcohol or lack of sleep, and your medicines, including how often you take painkillers. The examination usually covers blood pressure, vision, pupils, eye movements, the fundus with an ophthalmoscope, the temporal arteries and a brief neurological check.

Many people need no tests because the pattern is diagnostic.

• Eye examination with pressure measurement: checks for glaucoma and optic nerve disease.

• Blood tests for inflammation (ESR, CRP): used when giant cell arteritis is possible.

• MRI brain: considered when there are neurological signs, an atypical pattern or cluster headache, to exclude a structural cause.

• Sinus CT: reserved for persistent, clearly sinus-type symptoms rather than as a first-line test for headache.

Keep a headache diary for four weeks, noting timing, triggers and medicines taken. Regular painkillers on more than about two to three days a week can themselves cause medication-overuse headache. Simple painkillers and rest suit a typical migraine or tension headache. Cluster headache needs specific treatment that a doctor prescribes.

A GP or optometrist is the usual first contact on the NHS. Referral to neurology or ophthalmology follows if the diagnosis is unclear. Privately, a direct consultant appointment with or without MRI is possible, but red-flag features should still be dealt with urgently through the NHS pathway.