Daily BulletinHoliday Centre

The Conversation

  • Written by Jason Yosar, Associate Lecturer, School of Medicine, The University of Queensland

Conjunctivitis is an eye disease that has been described since antiquity. Ancient Roman oculists, the eye physicians of the time, prescribed remedies such as vinegar lotions and copper oxide for its treatment.

Though the treatments have changed over the last 2,000 years, the disease has not. Conjunctivitis is inflammation of the conjunctiva, the normally transparent membrane that sits atop the sclera (the white part of the eye). It can affect one or both eyes and commonly causes redness, grittiness, irritation, itchiness and discharge that can be watery (like tears) or sticky (pus).

The conjunctiva: the eyeball’s protective coat

The conjunctiva is a thin, transparent mucous membrane that is about 33 microns thick (roughly the same thickness as two sheets of cling wrap stuck together). It lines the front part of the eyeball over the white sclera as well as the inner aspect of the eyelids, forming a continuous layer that physically prevents debris such as fallen eyelashes from migrating to the back of the eye socket.

The conjunctiva secretes mucus and tears to help lubricate the eye, and contains immune cells and tissue that help to prevent infection. Its rich supply of blood vessels dilate in response to irritation and inflammation. This leads to the distinctive red eye that occurs in conjunctivitis, dry eye, tiredness and other eye diseases.

Conjunctivitis may be divided into three main categories according to cause.

image The conjunctiva is the eye’s protective coating. Intech - Science, Technology and Medicine open access publisher.

Viral conjunctivitis

Viral conjunctivitis is the most common form of infectious conjunctivitis. A virus called adenovirus (which also causes respiratory infections and diarrhoea) is responsible for 65-90% of all cases of viral conjunctivitis. Other viruses, such as herpes simplex virus (also responsible for cold sores) and varicella zoster virus (also responsible for chicken pox), can also cause conjunctivitis.

The affected eye is red, itchy, irritated and gritty and produces watery discharge similar to tears. The virus commonly affects one eye first before quickly spreading to the other eye. It may be accompanied by a sore throat or runny nose typical of a common cold.

It occurs more frequently in adults than in children. Eye secretions and droplets from the respiratory tract of infected people transmit the virus. Because it is highly contagious, it often causes epidemics in schools and workplaces and among household members.

No effective antiviral medication currently exists for viral conjunctivitis. Antibiotic eye drops are not effective.

Treatment is aimed at symptom relief. This involves lubricating eye drops, cold compresses and antihistamine eye drops (if itching is troublesome).

The disease usually self-resolves in two to three weeks.

Bacterial conjunctivitis

Bacterial conjunctivitis is less common than viral conjunctivitis. It is caused by bacteria such as Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis and Haemophilus influenzae.

These bacteria are members of the normal colonies living on healthy eyes and usually do not cause disease. However, they can proliferate and cause conjunctivitis in certain conditions, such as dry eye, after damage to the eye, or in a weakened immune system. More commonly, though, these bacteria simply cause conjunctivitis when transmitted from an infected person to a non-infected person.

Like viral conjunctivitis, bacterial conjunctivitis is contagious. One or both eyes may be involved and they are also red, irritated and gritty. However, bacterial conjunctivitis usually produces a sticky whitish or yellowish discharge like pus, in contrast to the watery tears of viral conjunctivitis.

Broad-spectrum antibiotic eye drops, such as chloramphenicol (Chlorsig, available over the counter at pharmacies), are effective in reducing how long the symptoms of bacterial conjunctivitis last. However, it is important to note bacterial conjunctivitis frequently resolves even without treatment.

Less commonly, Neisseria gonorrhoeae (gonorrhoea) and Chlamydia trachomatis (chlamydia) can cause conjunctivitis. These typically occur in sexually active young adults with direct or indirect eye exposure to infected genital secretions, or in babies born via vaginal delivery to infected mothers.

These diagnoses should be suspected in any case of conjunctivitis that features excessive pus-like discharge, or fails to respond to standard antibiotic eye drops. These conditions should be assessed promptly by an ophthalmologist.

Allergic conjunctivitis

Allergic conjunctivitis is triggered by exposure to allergens. These include pollen, dust mites and animal dander (microscopic flecks of skin). Because it is not caused by micro-organisms, this condition is not contagious and avoiding school or work is not required.

Redness, itchiness and watering of both eyes are the prominent features. These may be accompanied by an itchy nose, itchy throat and sneezing.

Identifying and avoiding the offending allergen(s) is important for treatment. This may require an allergy test.

Symptom relief can be achieved through lubricating eye drops, cold compresses and antihistamine eye drops and tablets. These are available over the counter at pharmacies.

However, eye drops containing the active ingredients antazoline and naphazoline (vasoconstrictors*, which reduce redness) should not be used for long periods as these may cause a rebound red eye when they are stopped.

image If antihistamine eye drops are taken for too long it can cause redness once the course is finished. www.shutterstock.com

I think I have conjunctivitis – what now?

It is important to note that pain, sensitivity to light and visual disturbances are not features of conjunctivitis. These may indicate a sight-threatening eye disease which requires urgent treatment by an ophthalmologist. A visit to the nearest hospital emergency department is warranted if any of these symptoms occur.

With any case of suspected conjunctivitis, first, stop wearing contact lenses (if you do) for the duration of the episode, and see your GP. If necessary, your GP can refer you to an ophthalmologist or ophthalmology walk-in clinic to ensure you do not have a more serious variety such as herpes simplex, varicella zoster, chlamydia or gonorrhoea.

People with viral or bacterial conjunctivitis should avoid work or school and public swimming pools until symptoms settle; avoid sharing towels and make-up items; avoid rubbing the affected eye(s); and practise thorough and frequent hand hygiene, especially after touching the face or eyes, sneezing or coughing.

Dr Cameron McLintock, ophthalmology registrar at Queensland Health, contributed to this article.

*This article originally said eye drops containing the active ingredients antazoline and naphazoline were antihistamines rather than vasoconstrictors, which reduce eye redness. This has now been corrected.

Authors: Jason Yosar, Associate Lecturer, School of Medicine, The University of Queensland

Read more http://theconversation.com/explainer-what-is-conjunctivitis-and-how-did-i-get-it-64230


The Conversation

Politics

Second Draft - Protecting religious freedom

PROTECTING RELIGIOUS FREEDOM REMAINS HIGH PRIORITY FOR GOVERNMENT   Our Government is committed to protecting every Australian from discrimination.   Today, we have released a second exposure ...

Scott Morrison - avatar Scott Morrison

Keeping Australians safe at airports

The Morrison Government is increasing counter-terrorism measures across nine airports by boosting the Australian Federal Police’s capability to disrupt and deter high-risk-incidents.   Prime Min...

Scott Morrison - avatar Scott Morrison

Scott Morrison on Medivac

PRIME MINISTER: The Australian public are in no doubt about our Government’s commitment to strong borders. Our Government has always been consistent. The Liberal and National parties have always b...

Scott Morrison - avatar Scott Morrison

Business News

Working at Heights: Why the Risks of Occupational Accidents Still Fall on Builders

In most cities and towns, the construction industry is booming, and all you have to do is look around you to figure out why. In addition to new homes going up all around you, businesses are needed a...

Alertforce - avatar Alertforce

Media and Capital Partners spins out new agency arm Mojo Media

Media and Capital Partners, one of Australia’s leading investor relations and media relations consultancies, has spun out a new, fully integrated consumer, finance and technology PR agency called ...

Media Release - avatar Media Release

How to make your small business survive and thrive in 2020

There’s a global downturn and Australian bricks and mortar retail is in a slump. 2020 is going to be a rough year. Everyone knows that, but a lot don’t know what to do about it. Australia still h...

Dorry Kordahi - avatar Dorry Kordahi

Travel

To sell travel packages partner with Holiday Centre - Advertisement

If you are a travel or accommodation provider allow the travel professionals at HolidayCentre.com market your products.. With a business name like Holiday Centre, you can be sure that they will delive...

Holiday Centre - avatar Holiday Centre

6 travel tips you need to know before visiting Melbourne

People have always held Melbourne in high regard with it's numerous coffee stops, it's glorious art galleries, the food scene that can floor any curious palate. There's a unique multiculturalism i...

News Company - avatar News Company

Hertz DriveU

Hertz and Air France launch Hertz DriveU, a new high-quality, hassle-free airport transfer service Hertz DriveU “When you don’t want to drive!” The service is available at more than 300 airports...

Media Release - avatar Media Release

ShowPo