What is a conjunctivitis in the eye?
The white of the eye and the inner surfaces of the lids are covered by a transparent membrane called the conjunctiva. Conjunctivitis is inflammation of the conjunctiva. Virus or bacterial infection can cause inflammation on the eye, edema and pain.
Symptoms of conjunctivitis
The white of the eye appears red or pink (bloodshot) as a result of the widening of the tiny conjunctival blood vessels. The conjunctiva contains thousands of mucus-secreting cells (goblet cells) and many minute tear-secreting glands.
Local irritation causes these to become overactive, so they water and discharge mucus. There may be a gritty sensation in the affected eye.
The discharge will often contain many white cells from the blood (pus cells), and the mucus and pus tends to accumulate on the lashes and in the corner of the eye, causing them to stick together.
If you have conjunctivitis, you may find it hard to open your eyes in the mornings.
Causes of a problem
Conjunctivitis is most commonly caused by infection. Almost any germ, whether a bacterium or a virus, may be responsible.
Conjunctivitis in a newborn must be attended to immediately. The real concern here is that the conjunctivitis might be the result of a gonorrhea infection acquired during birth from an infected mother.
Allergic conjunctivitis is common and is occasionally dramatic.
Pollen hypersensitivity (hay fever) can cause the conjunctiva to swell and much fluid to collect behind it, so that the membrane bulges alarmingly forward between the lids.
Conjunctivitis can also result from a wide range of other causes, including:
- Toxic influences, such as chemical contamination from dusts, liquids, gases, industrial vapours or unsuitable medication.
- Radiation of various kinds, especially the ultraviolet in sunlight.
- Too much wind blowing on the eyes.
- Rarely, irritation from mascara and eye liner.
- Lack of moisturizing (syndrome of a dry eye).
How to diagnose conjunctivitis?
In most cases the diagnosis of conjunctivitis is fairly obvious. However, there are other cases of red eye that are not due to conjunctivitis and that are much more serious. Pain and loss of vision should be reported urgently.
Other conditions that cause redness of the eye include:
- Acute uveitis – inflammation of the iris and the focusing muscle.
- Corneal ulceration – commonly caused by the herpes simplex virus, but it may be caused by almost any germ.
- A foreign body on the cornea or under a lid.
- A sudden rise in the pressure within the eye (acute glaucoma).
- Bleeding under the conjunctiva (sub-conjunctival hemorrhage).
Bleeding under the conjunctiva is usually harmless unless there has been a very recent severe head injury. In this case it might indicate a skull fracture. Most cases of sub-conjunctival hemorrhage, however, are simply due to the breaking of a small сonjunctival blood vessel and are harmless. The blood will be absorbed in about a week.
How to treat conjunctivitis?
In some cases of infectious conjunctivitis the treatment may include antibiotic drops or ointment but this will depend on the symptoms and may only be prescribed in acute cases.
In non-infectious cases, steroid drops are sometimes prescribed. These will quickly relieve inflammation but may be dangerous. If the redness is due to an infection with herpes germs, steroid drops could cause a lifetime of recurrent pain and disablement and serious loss of vision in the affected eye.
Steroids should never be put into an eye except by an eye specialist.
It is important that any newborn baby with sticky or inflamed eyes should be urgently treated. The doctor will take a swab for identification of the organism and will start effective antibiotic treatment at once.