indoor and outdoor air pollution caused, for example, by chemical vapors, fumes, smoke, or dust
fungi
ameba and parasites
It can be difficult to determine the exact cause of conjunctivitis because some symptoms may be the same no matter the cause.
Viral Conjunctivitis
Caused by infection of the eye with a virus
Can be caused by a number of different viruses, such as adenoviruses
Very contagious
Sometimes can result in large outbreaks depending on the virus
Bacterial Conjunctivitis
Caused by infection of the eye with certain bacteria
Can be caused by Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, or, less commonly, Chlamydia trachomatis and Neisseria gonorrhoeae
Can be spread easily, especially with certain bacteria and in certain settings
A leading cause of children being absent from daycare or school [1]
More common in kids than adults
Observed more frequently December through April
Allergic Conjunctivitis
The result of the body’s reaction to allergens, such as pollen from trees, plants, grasses, and weeds; dust mites; molds; dander from pets; medicines, or cosmetics
Not contagious
Occurs more frequently among people with other allergic conditions, such as hay fever, asthma, and eczema
Can occur seasonally, when allergens such as pollen counts are high
Can also occur year-round due to indoor allergens, such as dust mites and animal dander
May result, in some people, from exposure to certain drugs and cosmetics
Conjunctivitis Caused by Irritants
Caused by irritation from a foreign body in the eye or contact with chemicals, fumes, smoke, or dust
Not contagious
Can occur when contact lenses are worn longer than recommended or not cleaned properly
