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Introduction and Overview
Most of us have heard the term "pinkeye" used to describe a condition where the eye appears to be red or pink-colored. Usually, the eye is also swollen and uncomfortable, with a sandy or gritty sensation; it may also feel hot, and there is usually a discharge, either watery, or thick and somewhat white, termed mucopurulent.
The conjunctiva is the clear membrane of tissue that covers the white of the eye. Essentially, it is a type of transparent skin, and contains tiny blood vessels which carry oxygen and nutrients to the insides of the eyelids and to the cornea, the clear, dome-shaped cover over the iris. The conjunctiva begins at the edges of the cornea where the transparent shield turns into the white sclera; it covers the white of the eye and lines the insides of the eyelids, ending where the line of eyelashes begins.
The "pink" in pinkeye happens because the conjunctiva is a vascular tissue; in the presence of infection or inflammation, those tiny blood vessels swell up and become more visible to the naked eye. The conjunctiva is vulnerable to infections and inflammation because it is exposed to the air. The term conjunctivitis may be used for any situation where the eye is pink or red; these can include the clear cornea too. When it does include the cornea, it is referred to as keratoconjunctivitis.
Sometimes, the redness may not be due to infection at all, but other causes like contact lenses or their soaking and cleaning solutions. Dryness, systemic illnesses or certain medications may also be at fault. Ultraviolet rays cause sunburn when we are outdoors too long without sunscreen; the conjunctiva is subject to the same effect, if it is not protected by good quality sunglasses on a sunny day.
Infections and allergies can be caused by particles floating in the air that have hitched a ride with us. When we rub our eyes with hands that are not pristine-clean, we can inadvertently inoculate ourselves with any number of bacteria or viruses, pollens or other toxic materials. In fact, rubbing the eyes with contaminated hands is probably the most common mechanism of spreading colds and influenza. Wash your hands often! This one simple thing goes a long way towards keeping us healthy.
Bacteria are one of the most numerous of life forms on the planet. It is much more likely than not for people to have several species of bacteria growing in their eyes; if we were to take samples with cotton swabs from the eyes of a hundred random people on the street, it is highly probable that all of them would have bacteria growing and living there. Fortunately, the immune system, a built-in and automatic defense mechanism prevents these common bacteria from multiplying and causing active infection. Occasionally, bacterial conjunctivitis may signal that there is a serious underlying systemic disease.
Your eyecare practitioner will determine the exact cause of the problem, since that will determine how to treat it.
Symptoms and Signs of Bacterial Infection
Usually, the infection and inflammation will appear in one eye only, although it can easily jump to the other eye.
Redness is usually the first thing patients notice, caused by the swollen blood vessels which are trying to bring in our infection-fighters, the white blood cells. The redness can range from a mild pinkness to a raging, hot, bright red. (Figure 1 shows a moderately red eye due to bacterial conjunctivitis.)
Irritation and swelling of the conjunctival tissue comes along with the redness; the eye may feel a sandy, gritty feeling that makes blinking uncomfortable. There may be a feeling of heat along with the redness, swelling and irritation, too; it is like a fever, only limited to the eye area.
In bacterial infections, there will almost always be a mucopurulent discharge from the eye, thicker than normal tears, and often it will appear white with tints of green or yellow.
These infections are highly contagious, and easily spread from one person to another. Someone who has conjunctivitis rubs his eye because it is irritated, then touches a doorknob, (or a telephone or a computer keypad or a shopping-cart handle), or shakes hands with you. A few minutes later, your eye itches and you rub it. Congratulations!
This is not only the way eye infections are spread, but the way systemic disease like colds and influenza are spread as well. Once the infectious particles are in the eye, they become mixed with the tears and, like driftwood floating down a river, they are carried into the nose and throat as the tears drain from the eye and can then blossom into an active infection.
Treatment of Bacterial Conjunctivitis
See your eyecare practitioner as soon as possible. The urgency of this situation will vary from being an irritating and annoying distraction all the way up to where the eye is extremely red, swollen and painful; serious bacterial infections can worsen by the hour.
Do not assume the redness is because you didn’t get enough sleep or because you may have partied a little bit too enthusiastically. First, these common culprits always affect both eyes, not just one, and second, they will disappear shortly after they are noticed.
Your eyecare practitioner will determine if the infection is viral or bacterial, or from one of a number of other possible causes. In bacterial infections, the usual treatment is to prescribe antibiotic eye drops, and oral antibiotics if the infection is severe. The treatment regimen may include steroidal eye drops as well, to quiet the inflammation response and make the eye a lot more comfortable. Rarely, the eyecare practitioner may patch the eye, but most practitioners avoid this if possible, because there are some bacteria that thrive in darkness and without oxygen. If the eye is patched at all, it is NEVER patched without using antibiotics first.
For symptomatic relief, cool compresses are helpful and can be done several times a day; however, the immune system causes the heat and there is some evidence that this helps the disease-fighting process be more effective.
Summary and Useful Tips
Bacterial conjunctivitis is a serious condition and should not be dismissed as “just pinkeye.” Some bacteria are extremely aggressive and can damage the eye and cause permanent vision loss. See your eyecare practitioner without delay, so treatment can begin while the infection is still in the “small brush-fire” stage, rather than the “raging inferno.”
These infections are commonly quite contagious. Stay home from work, or keep a child with a red eye home from school until your eyecare practitioner advises that it’s OK to go back.
While viral infections, like colds or influenza, are usually self-limiting and require no antibiotics, your eyecare practitioner may decide to prescribe them to help prevent a secondary infection from bacteria, because the eye is vulnerable.
Do not apply a patch to the eye unless you are instructed to do so by your eyecare practitioner.
Prevention of eye infections and bacterial conjunctivitis is mostly as simple as washing your hands often. There is some controversy about whether anti-bacterial soaps are a good idea for general use, (some physicians are concerned that widespread use of antibacterials can lead to more virulent strains, and cause more problems than they solve) but when there is an active, acute infection present, they are probably a good way to keep it from spreading within the immediate environment and protect others in the home from being inoculated.
