What should you know about acute conjunctivitis?

Typical features include redness, grittiness, watering or discharge. The cause matters because antibiotics only treat susceptible bacterial infection; they do not help viral or allergic conjunctivitis. Eye pain, reduced vision, marked sensitivity to light or chemical exposure requires a different level of assessment.

The conjunctiva is the thin membrane over the white of the eye and inner eyelids. Viral conjunctivitis often begins with watering and may occur alongside a cold. Bacterial infection can produce thicker discharge that makes the eyelids stick together. Allergy tends to affect both eyes and causes prominent itching, often with sneezing or a runny nose.

Redness can have causes other than conjunctivitis. A scratched cornea, inflammation deeper inside the eye, glaucoma or a retained foreign body may also cause a red eye. Pain, vision change and strong light sensitivity make these alternatives more concerning and should not be managed as routine conjunctivitis without examination.

Gently clean crusts with clean water and a fresh pad for each eye. A cool compress may soothe irritation. Avoid rubbing, sharing towels, eye cosmetics and contact lenses until symptoms have resolved and any clinician instructions are complete. Wash hands before and after touching the face, and clean frequently handled items to reduce spread when infection is possible.

A pharmacist or clinician can advise on symptom relief and whether an examination is needed. Do not use leftover antibiotic or steroid eye drops. Steroid drops can worsen some infections and should only be used under eye-care supervision. If prescribed drops, complete them as directed and avoid touching the bottle tip to the eye or lashes.

Arrange urgent same-day assessment for moderate or severe eye pain, reduced or distorted vision, marked light sensitivity, a very swollen eye area, a cloudy cornea, an irregular pupil or worsening symptoms. Contact-lens wearers with a painful red eye need prompt examination because corneal infection can threaten sight.

After a chemical splash, rinse the open eye immediately with plenty of clean lukewarm water and seek emergency advice; do not wait for redness to develop. Emergency care is also appropriate after a penetrating injury or when something appears embedded. Babies with red eyes or discharge should be assessed promptly, particularly in the newborn period.

Tell the clinician whether one or both eyes are affected, what the discharge looks like, and whether pain, light sensitivity or vision change is present. Mention contact-lens use, recent respiratory illness, allergies, injury, chemical exposure and eye treatments already tried. Ask when lenses and cosmetics can safely be used again and how long to follow any prescribed treatment.