Conjunctivitis
Infection or inflammation of the conjunctiva, the clear membrane over the white of the eye and inside the lids. Viral conjunctivitis is watery and gritty, often follows a cold, spreads from one eye to the other and to other people, and clears on its own in one to three weeks. Bacterial conjunctivitis produces sticky discharge and lids glued on waking, and clears faster with antibiotic drops. Neither affects vision or causes real pain, which is how they are distinguished from corneal infection.
Eyelid infections
A stye is an infected lash follicle or gland at the lid margin: a tender red lump that comes to a head and drains within days, helped by warm compresses. A chalazion is a blocked gland deeper in the lid that is usually not infected. Blepharitis is chronic inflammation of the lid margin with bacterial overgrowth or demodex mites, managed with lid hygiene. Preseptal cellulitis is infection of the lid skin itself, with a swollen, red, warm lid, and is treated with oral antibiotics.
Corneal infections
Keratitis, infection of the cornea by bacteria, viruses, fungi or amoebae, is the infection that threatens sight. It causes pain, light sensitivity, redness, watering and blurred vision, often with a visible white spot. Contact lens wear is the main risk. It is treated the same day with intensive drops after cultures are taken, and it can scar. The corneal infection pages describe each type.
Rare and serious
Orbital cellulitis, infection of the tissues behind the eye, causes a swollen lid with fever, pain on eye movement and a bulging or restricted eye, usually spreading from the sinuses; it needs hospital treatment. Endophthalmitis, infection inside the eye, usually follows surgery or a penetrating injury and causes rapidly worsening pain and vision; it is an emergency treated by a retina specialist. Both are rare and both are recognized by their severity.
Preventing eye infections
Wash hands before touching the eyes or handling lenses. Never sleep, swim or shower in contact lenses, never rinse them in tap water, and replace them and their case on schedule. Do not share towels, eye makeup or drops. Replace eye makeup regularly. Treat blepharitis so the lid margin stays healthy.
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Nothing on this page is a diagnosis. Whether this is what is affecting your vision is decided by a full examination at one of our 4 offices: Pasadena, Huntington Beach, Woodland Hills and Beverly Hills.
About this content: This page was written with the assistance of AI tools and reviewed for medical accuracy by Dr. Bavand Youssefzadeh, DO. It is general information, not medical advice, and does not replace an eye examination. Individual results vary. Read our medical disclaimer.
