Infective conjunctivitis occurs when the conjunctiva (the thin layer of cells covering the white of your eye and the inner surface of your eyelids) becomes inflamed as a result of an infection. There are a variety of factors which can cause an infection to develop in your eye. The three most common causes are:
- bacteria,
- viruses, and
- sexually transmitted infection (STI).
There are no particular signs or symptoms that will allow your doctor to distinguish between a bacterial infection and a viral infection. Both types of conjunctivitis will normally heal by themselves. If your conjunctivitis is caused by a sexually transmitted infection (STI), such as chalmydia, it will usually result in your conjunctivitis lasting for several months, rather than weeks.
If your condition is persistent, you will have an eye swab to determine the cause of the infection (see 'diagnosis' section). If your infective conjunctivitis is caused by an STI, you will have to undergo screening and treatment for the infection. Newborn babies can develop conjunctivitis if the mother has Chlamydia because the infection is often passed to the baby during birth.
Spreading the infection
You are more likely to develop infective conjunctivitis if you have been in close contact with someone who is already infected. It is therefore very important that you make sure that you wash your hands thoroughly after coming into contact with someone who has the condition.
Diagnosing infective conjunctivitis
In most cases of infective conjunctivitis, your consultant will be able to diagnose the condition from your symptoms and by examination. Red, swollen eyes, which are covered in a sticky discharge, are very common features of infective conjunctivitis.
Some conditions which may cause reddened eyes are outlined below.
- Acute glaucoma - this is a rare form of glaucoma which causes a build up of pressure in the eye. Symptoms of pain, and loss of vision, can develop very rapidly. Left untreated, acute glaucoma can result in a permanent loss of vision.
- Keratitis - this is when your cornea (the clear layer at the front of your eye that allows light to travel through your eye) becomes inflamed, and sometimes ulcerated. In severe cases, this can cause scarring of the cornea, which can lead to a permanent loss of vision.
- Iritis - this condition causes your iris (the coloured part of your eye, behind the cornea) to become inflamed. If you have iritis, and it is not treated, it can cause the iris to stick to the front surface of the lens, which prevents fluid draining from the pupil. This can cause permanent damage to the eye.
Swab test
If your doctor is unsure about the diagnosis, or needs to determine the cause of your infection, they may have to take a swab from your infected eye. This will be tested in a laboratory to find out the cause of your condition. Your doctor can then provide you with the most appropriate treatment.
While your doctor is awaiting the results of your swabs, you may be prescribed a short course of antibiotics to help keep your symptoms under control. When your doctor finds out the results of the swab, you will then be prescribed the most suitable form of treatment for the cause of your condition.
Newborn babies
If your baby is 28 days old or younger and displays symptoms of infective conjunctivitis, it is important to contact your doctor straight away. Many babies may have what is known as a 'sticky eye'. This usually occurs when the tear (lachrymal) duct cannot drain properly. If it cannot drain, it produces a discharge of pus, which can look similar to infective conjunctivitis. However, this condition is not serious, and does not require urgent treatment.
If your baby also has redness in their eye, it may be a sign that the eye is infected. Your doctor will examine your baby closely to see if this is the case. Any newborn babies with infective conjunctivitis must be referred to an eye specialist (ophthalmologist) straight away, so that their condition can be managed and treated to prevent any damage occurring to the eye. Infective conjunctivitis in newborn babies (neonatal conjunctivitis) can, in rare cases, cause serious complications (see 'complications' section). However, with prompt treatment, most babies will make a full recovery.