1. Your Sight
  2. Eye infection - Infectious conjunctivitis
Man applying eye-drops

Eye infection – Infectious conjunctivitis

The following medical information does not constitute professional medical advice. If you have any specific questions about any medical matter, you should consult your doctor or professional healthcare providers.


If your eye or eyes are red, water, sting, itch, discharge or you have a foreign body sensation, it may well be that you have caught an eye infection.

An eye infection is an eye disorder caused by bacterial, viral, or fungal agents. The following text refers to the special case of conjunctivitis, even more specifically, to infectious conjunctivitis. 

Conjunctivitis is an inflammation of the conjunctiva (a thin transparent tissue covering the white part of the eye and the inside of the eyelids). It is often due to an infection - bacterial or viral - an allergic reaction or sometimes caused by a foreign body in the eye. It usually affects both eyes at the same time, but it may also occur in one eye only. Normally conjunctivitis is not very painful. 


Infectious conjunctivitis can be caused by bacteria, such as Staphylococci, Streptococci and Pneumococci, and, especially in children, by bacteria belonging to the Haemophilus group. Also viruses are typical causes of infectious conjunctivitis. 


Please consult a healthcare professional who can diagnose infectious conjunctivitis by its symptoms and appearance. When examining the eye with a slit lamp, the doctor may find conjunctival redness (the white part of the eye is bloodshot, more in the edges than in the middle) and that pus-like, white or yellow discharge is present. A slit lamp is an instrument that allows inspecting the eye under high magnification. If the condition lasts for a long time, samples of infected secretions may also be analysed to identify the infecting organism. Blood is not routinely used in diagnosing eye inflammation.

Allergic conjunctivitis may sometimes be confused with infectious conjunctivitis. In allergic conjunctivitis there is less discharge (the discharge is typically clear and elastic) and the symptoms last significantly longer.


Only a doctor can recommend the right treatment, but everyone who has conjunctivitis should follow one simple rule: don't touch or rub your eyes!

Eye infection used by bacteria is usually treated with (topical, i.e. local) antibiotics*, more specifically, with antibiotic eye drops and ointments, normally taken for 3-5 days. If the infection does not disappear within this period of time, you should consult your ophthalmologist again.

*The use of antibiotics should be restricted and under control of the prescribing physician in order to prevent development of resistance.