Eye infection (bacterial)

What is a bacterial eye infection?

A bacterial eye infection refers to an eye infection that is caused by the presence of bacteria. The most common bacteria known to cause conjunctivitis are Haemophilus influenza, Streptococcus pneumoniae and Staphylococcus aureus. These create an inflammation of the tissue inside the eyelid and on the surface of the eye. ^[1]

Bacterial eye infections can cause itchy and watering eyes, a discharge of mucus, or a sticky coating on your eyelashes.

Who gets bacterial eye infections?

Bacterial eye infections are very common, and affect nearly all of us at some point, though some people can be more prone to them than others. You may be more at risk if you:

• are a child or are elderly (possibly because children encounter infections at school, and elderly people tend to have a weakened immune system due to their age)
• have recently suffered from an upper respiratory tract infection, like a cold
• have diabetes and other conditions that can weaken the immune system and make you more vulnerable to picking up an infection
• are currently prescribed steroids (these can weaken the immune system)
• have blepharitis (a condition which causes an inflammation of the eyelids)
• have been in a crowded space like a busy bus or a train

How can I prevent getting a bacterial eye infection?

It’s difficult to prevent a bacterial eye infection, but there are some things you can do to lessen your chances of picking one up. For example, maintaining good hygiene, regularly washing your pillows and towels, and keeping your contact lenses clean (wearing them as directed) can help lessen your chances of catching an infection.

It’s always good practice to avoid sharing makeup too, and avoid people who currently have conjunctivitis (if you do come into contact with someone who has it, wash your hands thoroughly), whilst also maintaining good overall health.

What causes bacterial eye infections?

The causes of bacterial eye infection may vary, but they may be triggered by:

• bacteria, such as the strains that are often found in ear and lung infections
• bacteria which cause sexually transmitted infections (STIs), like gonorrhoea or chlamydia

Eye infections can be caused by different bacteria, sometimes causing different symptoms. For instance, conjunctivitis caused by the Morax-Axenfeld diplobacilli bacteria often lasts much longer than other forms of bacterial conjunctivitis and may require further treatment. However, bacterial eye infections are most commonly caused by bacteria similar to that which causes respiratory infections.

By extension, there are several types of conjunctivitis, such as allergic conjunctivitis’ which can be caused by:

• pollen
• dust mites
• contact lenses
• chlorinated water
  found in swimming pools
• certain shampoos
• fumes or smoke
• stray eyelashes which rub against the conjunctiva (tissue that covers the white area of the eye and the inside of the eyelids)

What are the symptoms of bacterial eye infections?

Symptoms of an eye infection will differ depending on the cause of infection. However, common symptoms of bacterial eye infections include redness and swelling, caused by the inflammation of the blood vessels in the thin layer of cells that cover the eyes, and unusual discharge. There is also sometimes a gritty or scratchy feeling. Symptoms tend to be experienced in just one eye to begin with, but usually affect both eyes within several hours.

Can bacterial eye infections lead to other problems?

Some bacterial eye infections can have serious complications if not treated. Conjunctivitis, for example, can lead to complications, depending on whether it’s infective or allergic conjunctivitis. There’s special concern around bacterial conjunctivitis that’s caused by sexually transmitted diseases, such as chlamydia and gonorrhea, which can threaten vision. Infective conjunctivitis, if left untreated, can lead to meningitis, or blood poisoning (septicemia), among other things. Another complication known as bacterial keratitis (bacterial infection of the cornea) can cause blindness if left untreated. If there are changes in your vision, you should get in touch with a clinician immediately.