Pink eye and vision loss

Say “pink eye” near any public health official, and you’ll strike terror into their hearts. “Pink eye” is not a medical term. It is a phrase commonly used to describe a type of eye infection that is highly contagious and that spreads rapidly through schools, offices, and the community. It can lead to visual loss.

When the eye gets red, or pink, we call it “conjunctivitis.” This is the medical way of saying, “the white part of the eye is inflamed and pink”. Conjunctivitis can have many causes. For example, the eye might be pink because a chemical, like hairspray, got into the eye. We call this “chemical conjunctivitis.” If the eye is red because of an allergy, we call it “allergic conjunctivitis”. If it’s red because of an infection, we call it “infectious conjunctivitis.” Pink eye is a type of infectious conjunctivitis.

Infections are commonly caused by two different kinds of microscopic life forms: bacteria and viruses. A common feature of bacterial infections is pus. A boil on the skin is caused by bacteria. Bacterial infections also commonly cause high fevers. Bacterial infections can be devastating, but luckily there are medications, called “antibiotics” that kill most bacteria.

Many infections are caused by viruses, of which there are hundreds of varieties or “strains.” For example, the common cold is caused by a variety of viruses. There is no specific medicine to kill most viruses. That’s why, when you catch a cold, there isn’t a pill that you can take to quickly make the cold go away. You just have to wait for your body to kill off the virus. In the meantime, you can take medications that treat the symptoms of the viral infection—like a decongestant for the runny nose, or a cough suppressant for the cough. But there just aren’t many anti-viral medications to get rid of the infection. Antibiotics don’t typically kill viruses, which is why we don’t often prescribe them for viral infections. In fact, use of antibiotics for viral infections can cause problems like the development of bacteria that are resistant to antibiotics.

Infectious conjunctivitis is caused by both bacteria and viruses. If the eye has a lot of pus, then the conjunctivitis is probably due to bacteria, and we prescribe antibiotics. If the eye is just pink and watery, then a virus is probably responsible.

Now, “pink eye” is a type of viral conjunctivitis caused by a specific family of viruses known as “adenovirus.” There are many different members of the adenovirus family, each with their own characteristics. But all of them are highly contagious. Pink eye, or “adenovirus conjunctivitis,” can spread very quickly through a community because it is spread by contact with the tears. This is part of the reason it is so worrying to those of us in the public health field. I tell my patients that the best way to prevent the spread of pink eye is to wash their hands frequently and to avoid touching their eyes. If you rub your eye, and then touch a doorknob, the next person who comes along and touches that doorknob and then their eye can get pink eye. It is easy to see how quickly the infection can spread through a community, and how important it is to wash your hands to avoid spreading it.

What’s the big deal about getting pink-eye? Well, there are three reasons you don’t want it. First, it can be pretty uncomfortable. Often the eye is irritated and painful. We can treat the symptoms, but it can still be pretty miserable. Second, many times we advise people to avoid going to work or school until they are no longer infectious. So you lose time from work and school. Finally, adenovirus can result in permanent scarring of the cornea. The cornea is that clear covering over the brown or blue part of the eye that lets light into the eye. If the cornea gets scarred, the vision can become permanently blurred.

It is because of the risk of visual loss that I recommend people with pink eye to see an eye specialist. If we catch the corneal problems early enough we can treat them, but if left untreated, they can leave permanent scars and lead to visual loss.

Every year or two we have epidemics of pink eye. The epidemic starts and spreads like wildfire through the community. With every epidemic we see people who seek care too late in the course of the infection, resulting in some permanent loss of vision. If you get a red, irritated, watery eye, seek care. Medicine can be prescribed to help the eyes feel better, and more importantly, to help prevent visual loss. The epidemic can be controlled by simple hand-washing.

(David Khorram, MD is a board certified ophthalmologist, and director of Marianas Eye Institute. Questions and comments are welcome. Call 235-9090 or email eye@vzpacifica.net. Copyright © 2005 David Khorram.)