Symptom guide

Start with what you notice.

Symptoms are the way most people first meet an eye problem. This guide helps you understand what a symptom might mean and how urgent it is.

Clinically reviewed · Last reviewed 2026-06-13

All symptoms A–Z

Blurred vision Sudden blurring needs urgent care Fuzzy or out-of-focus vision; often a focusing problem, but sudden blurring in one eye needs urgent care. Red eye Painful red eye needs urgent care A red or bloodshot eye; usually harmless, but pain, light sensitivity or vision changes need urgent care. Eye pain Severe eye pain is an emergency Aching, sharp or gritty eye pain; some causes are minor, but severe pain with vision changes is an emergency. Itchy eyes Usually not an emergency Itchy, irritated eyes; most often allergy or eyelid irritation, and rarely an emergency. Dry, gritty eyes Usually not an emergency A dry, gritty or burning feeling; usually dry eye or blepharitis, and manageable with simple care. Flashes and floaters A sudden increase is an emergency Spots that drift and brief flashes of light; often harmless, but a sudden increase is an emergency. Double vision Sudden double vision needs urgent care Seeing two images of one object; a new or sudden onset needs prompt assessment. Light sensitivity Pain with light sensitivity needs urgent care Discomfort in bright light; often from surface irritation, but pain with light sensitivity needs urgent care. Watering eyes Usually not an emergency Eyes that water too much; usually minor, from dryness, irritation or blocked tear drainage. Sudden vision loss Medical emergency: seek care now A sudden drop in vision is a medical emergency and needs immediate eye care. Eye discharge Usually minor; some signs need urgent care Sticky, watery or crusty discharge; usually conjunctivitis or blepharitis, but pain or vision changes need urgent care. Swollen eyelid Spreading redness needs urgent care A puffy or swollen eyelid; usually a stye, chalazion or allergy, but spreading redness needs urgent care. Eye strain Uncomfortable but not harmful Tired, achy eyes and headaches after close or screen work; eased by breaks and the right glasses. Halos around lights Sudden painful halos are an emergency Rings or glare around lights; often cataracts, but sudden halos with pain and redness are an emergency. Difficulty seeing at night Get checked if it is worsening Poor night vision; often cataracts or uncorrected sight, but progressive loss can signal a retinal condition. Cloudy vision Sudden clouding needs urgent care Hazy or milky vision; often cataracts, but sudden clouding in one eye needs urgent care. Burning eyes Usually not urgent unless the eye is painful and red A hot, stinging feeling in the eyes; usually dry eye or allergy, but a painful red eye needs urgent care. Distorted vision New distortion needs prompt assessment Straight lines look wavy or bent; can signal macular disease and needs prompt assessment. Peripheral vision loss Sudden side vision loss needs prompt care Losing side vision or feeling like you are looking through a tunnel; can signal glaucoma or retinal disease. Pressure behind the eye Painful pressure with vision changes needs prompt care A fullness or pressure feeling behind or around the eye; often benign but can relate to glaucoma or sinus problems. Feeling of something in the eye Chemical splash or high-speed injury needs urgent care Gritty, scratchy sensation as if something is stuck; often dry eye or a foreign body, but persistent feeling needs checking. Yellow eyes Yellow sclera may signal jaundice — see a doctor Yellowing of the white of the eye; often signals jaundice from liver or gallbladder disease and needs medical assessment. Leukocoria (white pupil reflex) Medical emergency in children: seek care today A white or pale pupil reflex in a child, especially in photos, is an emergency that needs same-day specialist assessment. Unequal pupils (anisocoria) New anisocoria needs prompt assessment Pupils of different sizes are often harmless if long-standing, but new anisocoria with pain or droopy lid needs urgent care.

Urgent symptoms

Seek same-day or emergency care for these.

Sudden vision loss
New flashes and floaters
A curtain or shadow over vision
Severe eye pain
Eye injury or chemical splash

Common everyday symptoms

Usually less urgent, but still worth understanding.

Dry, gritty or watery eyes
Blurry near or distance vision
Eye strain and headaches
Mild redness or irritation

How we rate urgency

Each symptom guide explains likely causes and gives a clear urgency level, so you know whether to monitor, book an exam, or seek emergency care.

Frequently asked questions

Which eye symptoms are an emergency?

Sudden vision loss, a new shower of floaters or flashing lights, a curtain or shadow over your vision, severe eye pain, or any eye injury need same-day medical care.

Are floaters always serious?

Occasional floaters are common and usually harmless, but a sudden increase, especially with flashes or a shadow, can signal a retinal problem and needs urgent assessment.

Why is my vision suddenly blurry?

Sudden blur has many causes, from dry eye to more serious issues. If it is sudden, persistent, or affects one eye, seek prompt medical advice.

What is the difference between red eye and bloodshot eyes?

They describe the same visible redness, but a painful bloodshot eye with light sensitivity or vision change needs urgent assessment, while mild redness with watering may be conjunctivitis or dry eye.

When should yellow eyes be checked?

Yellowing of the white of the eye (sclera) often signals jaundice from liver or gallbladder disease. See a doctor promptly — this is usually a medical rather than routine optician issue.

Can stress cause eye symptoms?

Stress can worsen dry eye, twitching, and migraine-related visual aura. It does not replace the need to check new vision loss, pain, or flashes urgently.

Should contact lens wearers treat red eyes differently?

Yes. Remove lenses at the first sign of pain, redness, or reduced vision and seek same-day advice. Infections can progress quickly in lens wearers.

What does double vision mean?

Seeing two images can come from eye alignment problems or, if sudden, more serious conditions including stroke. Sudden double vision with weakness or speech changes is an emergency.