Eyes and Ears

Conjunctivitis

What are the symptoms of this condition?

Conjunctivitis produces symptoms of intense itching, burning or grittiness beneath the eyelids. The affected eye or eyes will be reddish in appearance; it usually affects both eyes. There may be a discharge around the eyelids, often very noticeable in the mornings with the eyelids being stuck together, and pronounced general redness of the whites of the eye. The condition will probably last for around seven to ten days, although sometimes this can be longer.

One important feature to note about conjunctivitis, and a symptom that distinguishes it from other more serious eye conditions, is that while it may produce discomfort it never produces pain. A painful red eye is not conjunctivitis and should be referred to a doctor immediately. Conjunctivitis does not affect the vision in the affected eye(s), apart from a slight blurring caused by excess tears or discharge. If vision is affected in any other way, you should consult your doctor.

What is the cause of the condition?

Conjunctivitis is usually, although not always, the result of an infection taking hold in the transparent mucus membrane (‘conjunctiva’) that covers the front part of the eyeball. This membrane not only covers the white of the eye it also lines the inner surface of the eyelids. Its purpose is to act as a protective surface for the white of the eye and as a moist lining for the eyelid. In its normal, uninfected state, the conjunctiva allows the lid to slide easily over the surface of the eye as it contains many cells that release mucus, a colourless lubricating liquid.

When the conjunctiva is inflamed and irritated the tiny veins and arteries of its blood supply, not normally seen, become enlarged. They become visible and so give the eye its reddish, inflamed appearance. The quantity of mucus being released can increase and will become thicker producing the sticky discharge found in many cases of conjunctivitis.

The majority of conjunctival infections are due to bacteria, the most common causative bacterium being Staphylococcus aureus. Other varieties of bacteria are sometimes involved and occasionally a virus may be responsible. They all cause the common symptoms of conjunctivitis: redness, itching, grittiness, burning and discharge. Distinguishing between these different causative bacteria is not possible without further investigations, and is not important when self-treating.

Inflammation of the conjunctiva can also result from an allergic reaction. This can be a reaction to a foreign substance coming into contact with the conjunctiva, perhaps eye makeup, or as part of a hayfever-like allergy to pollens (termed ‘vernal’ conjunctivitis as it often occurs in the springtime). The symptoms are similar to the infective type of conjunctivitis although the treatment required is different.

What complications might occur?

Bacterial conjunctivitis will usually settle down without any further complications. Allergic conjunctivitis will also usually do the same. Rarely, infective conjunctivitis may spread to the surrounding structures of the eye. The cornea (the transparent structure in front of the pupil and iris) may become involved; this is a serious complication, as damage to the cornea will permanently affect the vision.

What can I do to treat myself?

There are two aims to the self-treatment of conjunctivitis: to remove the underlying infection, and to relieve the discomfort.

Controlling the infection 
Most episodes of conjunctivitis are due to a bacterial infection. As such it is easily transmitted from one family member to another, and from an infected eye to an uninfected eye.

That being the case, certain basic measures are necessary to limit the spread of the infection.

Separate towels and flannels should be provided for the person with the infection and these kept separate from those used by other family members. They should also be carefully laundered to ensure that all the bacteria are removed. When cleaning or wiping the eye it is better to use disposable tissues rather than a handkerchief as the tissue can be immediately disposed of. The same tissue should not be used for wiping or cleaning both eyes, as this will transfer the infection. After touching or cleaning the eyes always thoroughly wash the hands – the bacteria can be passed from person to person in this way.

If the conjunctivitis is known to be due to an allergy rather than an infection, the above measures are not necessary. However, if there is any doubt about the cause it would be better to act as if it were an infection. These precautions will do no harm in either case.

Relieving the symptoms
Although conjunctivitis is never painful, it can be very uncomfortable. There can be a lot of inflammation and a sticky discharge, making the eye feel as if it is full of sand.

Warm compresses to the eyelids can help to improve the situation; the warmth improves the circulation through the eyelids and conjunctiva,which in turn brings extra white cells (cells in the blood which fight infection) to the infected area.

Gentle cleaning of the eyelids with warm water will bring some relief, especially if this is timed to coincide with the compresses. Lid cleaning should be undertaken with cotton buds soaked in warm water. Each bud should be used for one wipe and then disposed of. The discharge can be quite thick so several attempts may be needed to remove it.

Eyedrops during the day and ointments at night can be used to ease the grittiness and discomfort. More details of these and other medications which can be used to treat conjunctivitis can be found in the next section.

Allergic conjunctivitis 
Conjunctivitis due to allergies will resolve once the allergen (substance causing the allergy) is removed. If it is a pollen allergy, this is more difficult; following the general treatment advice for hayfever (covered in a separate topic) will help. Foreign body conjunctivitis is often due to make-up coming into contact with the conjunctiva. The solution here is to stop using the make-up or change to a different brand. General care and cleaning of the eye may still be needed.

What treatments are available from my doctor?

Your doctor will be able to supply more potent antibiotic eye drops on prescription if the conjunctivitis is proving particularly troublesome.

What additional investigations might be needed?

Rarely, the infection may be deep-seated and difficult to treat, and may appear to spread to other structures of the eye. It may also be due to an allergic reaction, as with vernal conjunctivitis. In these cases a specialist examination of the eye by an ophthalmologist may be required. Samples will be taken of the discharge and also the tears to try and determine the cause exactly.

Any other information I should have?

The red eye of conjunctivitis can look quite dramatic. Other eye conditions can also cause a red eye; the most important sign that distinguishes the relatively harmless conjunctivitis from potentially much more serious eye conditions is the presence of any pain. Conjunctivitis does not cause pain, only discomfort in varying degrees. An eye that is red and painful needs to be seen by a doctor as a matter of urgency. It could indicate glaucoma or inflammations occurring in the cornea or deep in the eye.