Eye health resource
3 Common Sources of Eye Infections
Eye infections can spread through contagious exposure, contact-lens and water-related risk, or injury and ocular-surface problems. Learn warning signs and when prompt eye care is important.
Reviewed for accuracy by Justin Bazan, OD on .
Eye infections do not all start the same way. Some spread from person to person, some are associated with contact-lens wear or water exposure, and others occur after an eye injury or when the eye's normal protective surface is compromised.
Redness alone does not prove that an eye is infected. Allergy, dry eye, inflammation, contact-lens irritation, and other conditions can look similar, so symptoms and examination findings matter.
1. Contagious Viral or Bacterial Conjunctivitis
Viral and bacterial conjunctivitis can spread through contact with infected secretions, contaminated hands, towels, cosmetics, or other shared items. Viral conjunctivitis is common and many cases are self-limited, while bacterial disease may require antibiotic treatment depending on the presentation.
Allergic conjunctivitis can also make the eyes red, watery, and itchy, but allergy is not contagious and is not an infection.
Good hand hygiene, avoiding eye rubbing, not sharing towels or eye cosmetics, and following clinician guidance about school or work can reduce transmission when infectious conjunctivitis is suspected.
2. Contact Lenses, Poor Lens Care, and Water Exposure
Contact lenses are medical devices. Most people wear them safely, but improper wear and care can increase the risk of microbial keratitis — a potentially serious infection of the cornea.
Risk rises with habits such as:
- sleeping in lenses when overnight wear has not been prescribed;
- wearing lenses longer than directed;
- poor cleaning or disinfection;
- reusing or “topping off” old solution;
- rinsing or storing lenses in tap water;
- showering or swimming in lenses;
- using a dirty or poorly maintained lens case; or
- sharing lenses with another person.
Water deserves special attention because tap, pool, lake, and hot-tub water can contain organisms that should not be trapped against the cornea by a contact lens.
3. Eye Injury or a Compromised Ocular Surface
An abrasion, foreign body, plant or soil injury, eyelid problem, severe ocular-surface disease, or weakened immune system can make the eye more vulnerable to infection. Some viral corneal infections, such as herpes simplex keratitis, can also occur when a previous viral infection reactivates rather than through a new exposure from another person.
Eye infections are not simply “genetic.” Newborn eye infections can sometimes be related to infectious exposure around the time of birth, but that is different from inheriting an eye infection through genes.
What Symptoms Can Suggest a More Serious Infection?
Warning signs include:
- increasing eye pain;
- significant redness;
- light sensitivity;
- sudden or worsening blurry vision;
- unusual tearing or discharge;
- a visible white spot on the cornea; or
- symptoms that worsen after contact-lens wear.
A contact-lens wearer with pain, redness, light sensitivity, or blurred vision should remove the lenses and seek prompt eye-care evaluation. Do not continue wearing the lenses until an eye-care professional says it is safe.
Does Every Red Eye Need Antibiotics?
No. Many red eyes are not bacterial infections, and unnecessary antibiotic or steroid drops can be unhelpful or, in some situations, harmful. Treatment depends on the cause.
An eye exam can distinguish among conjunctivitis, keratitis, dry eye, allergy, eyelid disease, contact-lens complications, and other causes that may look similar at home.
Eye Infection Care at Park Slope Eye
Park Slope Eye provides medical eye care for appropriate non-emergency eye-health problems and contact lens care.
If you have an urgent but non-emergency eye concern, email us as well as using the available phone contact so the office can help determine the appropriate next step. A true emergency, severe injury, chemical exposure, or sudden major vision loss requires prompt emergency evaluation rather than waiting for a routine office visit.
Originally published . Substantially updated .