What is Conjunctivitis?
What is conjunctivitis?
Conjunctivitis is an inflammation of the conjunctiva, which are the membranes covering the whites of the eyes and inner eyelids. Because of its location, the conjunctiva is exposed to many microorganisms and other harmful environmental factors. It is a very common eye condition, usually benign in nature, although it may cause serious disorders of the visual apparatus. It usually affects both eyes simultaneously, although it may start in one eye and spread to the other, one or two days later. May be asymmetrical, affecting one eye more than the other.
What causes conjunctivitis?
There are three types of causes of conjunctivitis:
- Infectious: bacterial, viral or chlamydia.
- Allergic reaction caused by some external allergen.
- Chemical or irritativeBacterial Conjunctivitis
Bacterial conjunctivitis is an infection caused by bacteria such as staphylococci, streptococci or haemophilus. Can be produced by hand-eye contact, unbalance the normal flora, pathogen-reflux through the tear ducts and inoculation of contaminated environment, such as dust and particles.
Viral Conjunctivitis
Viral conjunctivitis is often associated with common cold. It can be caused by different viruses such as adenovirus, producing sometimes conjunctivitis and pharyngitis boxes associated. This type of conjunctivitis can spread rapidly between people and can produce an epidemic of conjunctivitis. Another virus that can affect the conjunctiva is shingles.
Chlamydia conjunctivitis
This type of conjunctivitis is caused by an organism called Chlamydia trachomatis. This organism can also affect other parts of the body and cause venereal disease (lymphogranuloma venereum). In countries with scarce health care resources is a major cause of blindness due to repeated infections that lead to trachoma.
Allergic conjunctivitis
Allergic conjunctivitis is common in people who have other symptoms of allergic diseases like hay fever, asthma and eczema. This type of conjunctivitis is often caused by antigens like pollen, dust mites or cosmetics. May be associated with rhinitis (inflammation of the nasal mucosa) and also have a seasonal nature.
Chemical or irritant conjunctivitis
They are due to the action of chemical and physical agents on the conjunctiva, most notably wind, smoke, ultraviolet light, and household chemicals. Many cases are caused by a subject’s special susceptibility to these agents.
credit to: Dr. Francisco Javier MartÃnez Saborido, Dr. Per Lykke Gregersen, Dra. Caroline MacEwen