Start with the symptom. Each entry says what it might be, when it is urgent, and which guide to open next. Nothing on this page is a diagnosis — it is a plain-English triage, cited to NHS, the American Academy of Ophthalmology and the National Eye Institute.
Get urgent care now if
You have sudden vision loss, severe eye pain, a chemical splash in the eye, a penetrating eye injury, or you see a curtain, shadow, or sudden shower of floaters and flashes. These can be medical emergencies. Go to an emergency department or call your local emergency number.
Sources: AAO — Sudden vision loss; NHS — Retinal detachment; NEI — Retinal detachment.
Vision in one or both eyes drops quickly, a "curtain" falls across your sight, or a central patch goes dark. Causes range from retinal detachment to a blood-vessel blockage in the eye. Treat as an emergency.
See also: AAO · NHS retinal detachment
Sudden bright flashes of light, or a sudden shower of new dark floaters, can be a sign the retina is tearing or detaching. The window for treatment is short. Get seen the same day.
See also: NEI — Retinal detachment · AAO — Flashes
Deep, aching eye pain — especially with nausea, haloes around lights, or a red eye — can be acute angle-closure glaucoma, a medical emergency. Get care the same day.
See also: AAO — Glaucoma · NHS — Glaucoma
Most red eyes are allergies, dry eye, or a simple infection and settle in days. A red eye with pain, blurred vision, light sensitivity, or discharge that is not clearing in 48 hours should be seen.
See also: AAO — Red eye · NHS — Red eye
Seeing two of everything is not normal. New double vision — especially if sudden or paired with a headache, weakness or trouble speaking — should be seen the same day, as it can be a sign of a stroke or nerve problem.
See also: AAO — Double vision
Rings or starbursts around lights can be normal at night, but new persistent haloes — especially with pain or blurry vision — can be a sign of corneal swelling, cataract or glaucoma.
See also: AAO — Halos
A tired, slightly blurry feeling at the end of a screen day is digital eye strain, not damage. Rest, blink, and try the 20-20-20 rule. If the blur does not clear with rest, see an optometrist.
A dry, sandy, burning feeling — often worse on screens, in dry air, or with contact lenses. Common in midlife. Lubricating drops and blink breaks help; persistent dryness needs a doctor.
See also: AAO — Dry eye
Itching and watering, both eyes, at the same time each year — likely allergic conjunctivitis. Antihistamine drops and avoiding the trigger help. See a doctor if it is in one eye only or paired with pain.
See also: AAO — Eye allergies
Fine print starts to blur in your 40s. This is presbyopia — the lens loses flexibility with age. Reading glasses, progressive lenses or multifocal contacts all correct it.
Occasional floaters are normal and more common with age. A sudden shower of new floaters, with flashes, is not — see the Urgent section at the top of this page.
See also: AAO — Floaters and flashes
Night-driving glare and slower dark adaptation become more common with age and with cataract. If it is new and getting worse, see an optometrist.
See also: NEI — Cataracts
This is editorial triage, not a medical device. It summarizes what the National Eye Institute, the American Academy of Ophthalmology and the NHS publish about common eye symptoms, with every claim linked back to the source.
Not medical advice. For any concern about your eyes, see an optometrist or ophthalmologist. For sudden vision loss, severe pain, injury or chemical exposure, go to an emergency department.