Medical Matters: What is conjunctivitis and how can it be treated?

written by Scally McDaid Roarty August 16, 2017

Continuing our very popular series, Medical Matters, well-known GP Ciaran Roarty, deals with the issue of conjunctivitis.


What is Infective Conjunctivitis?
Conjunctivitis is a very common condition in which either or both eyes become red and there may be a watery or sticky discharge. The conjunctiva is like a very thin skin that runs over the underside of the eyelids and the white part of the eye. In conjunctivitis this fine layer becomes inflamed.

The eyes feel gritty and uncomfortable with redness and discharge. It can happen at any age. The usual cause in children is a bacteria whilst in adults viruses tend to be to blame. Whilst usually a harmless condition albeit very contagious, it is useful to know how to manage it.

The exception to the rule is conjunctivitis in the newborn baby which needs urgent medical attention. It can be differentiated from the very common blocked tear duct in babies because a blocked tear duct does not cause reddening of the conjunctiva.

The conjunctiva does not cover the coloured part (iris) or dark centre (pupil) and therefore does not affect vision – except when a large amount of discharge smears over the surface of the eye, but this clears on wiping away.


What are the symptoms Doctor?
Symptoms of infective conjunctivitis are generally mild and usually the eye feels uncomfortable or gritty rather than painful. The most noticeable feature is a pink or red looking eye. It often starts in one eye but can spread to both. The white of the eye looks inflamed.

The eyes water more than usual and may become a little sore if you rub them. The eyelids may swell and may stick together after sleeping with a gluey material. This is common in bacterial conjunctivitis. Vision is not normally affected except, as described above, due to discharge. The signs and symptoms outlined will generally give you the diagnosis.

Conjunctivitis associated with more severe symptoms such as severe pain or profuse discharge should be seen by your doctor. Certain symptoms are suggestive of another cause for your eye symptoms and urgent medical advice should be sought. These include:

Changes in vision (other than smearing as described), severe pain, inability to open the eye, extreme sensitivity to light, inability to focus, flashing lights, headache, vomiting or distorted images.


Causes of Infective conjunctivitis:
Infection with germs ( bacteria or viruses) cause infective conjunctivitis but conjunctivitis may also be due to allergy (eg hayfever) or irritation (eg chlorine from swimming pools or shampoo in your eyes). Of the infective causes bacteria tend to predominate in children while viruses tend to be the cause in adults.

The vast majority of cases of infective conjunctivitis are not serious. Most bacterial cases are usually mild and clear within a week without antibiotics. Most viral cases are caused by a virus called Adenovirus which causes a very red and longer lasting conjunctivitis ( up to a few weeks). This means that you should see a doctor.

Other rarer but serious causes include bacterial causes of conjunctivitis in the newborn which are acquired during birth. STI causes of conjunctivitis such as chlamydia or gonorrhoea cause severe symptoms and need urgent treatment. Some other virus causes of conjunctivitis such as the cold sore virus or shingles virus cause severe pain and require medical attention.

Infection deep within the eye will cause decreased vision or swelling around the eye. Other conditions which make the eye red but are not infections include uveitis and acute glaucoma. Most of these will markedly affect vision and require medical attention and significant pain relief.


How do I treat this infective conjunctivitis Doctor?
Mild or moderate infections settle within a week due to chemicals within the tears. Bathing the eyes with cool clean water and using lubricating eye drops will help. Antibiotic drops may be prescribed for more severe cases.

It is also useful to not wear contact lens until symptoms are well gone and not share towels, pillow etc with someone affected. Handwashing and cleaning secretions with cotton wool soaked in water helps. Adenovirus conjunctivitis settles within 2-4 weeks usually and antibiotic drops may be prescribed to prevent further bacterial infection. Cold compresses and lubricants help also.


Important things to watch out for:
You should see your doctor if symptoms change or do not improve within a few days, or if you have concerns about a more serious cause. Attend urgently if you notice marked pain in the eye, pain associated with light, spots or blisters on the skin near the eye, changes in your vision or conjunctivitis in your newborn baby.

Thankfully most conjunctival infections are not serious.

The above information is intended as advice only and should you have any concerns contact your own Doctor.

Dr Ciaran Roarty MB BCh BAO MICGP DRCOG is a full-time GP at Scally McDaid Medical Practice , Scally Place, Letterkenny, Tel 0749164111



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