Summertime means fun: You go swimming, have adventures on camp-outs and spend long afternoons reading in an air-conditioned library.

You don't have to go to school. The ice cream truck drives through your neighborhood every afternoon. Your family takes a trip to the mountains or the beach -- the list goes on and on.

But there are some down sides to summer, too: It's TOO HOT! You get bored when your friends are out of town and you're still stuck at home. You get poison ivy. Mosquitoes get into your tent on a camping trip. Your hay fever kicks up. There are jellyfish in the water at the beach.

But at least there's nothing bad in the water at the pool . . . until you develop a case of summer "pink eye" from the chlorine in the water.

Most kids have experienced the nasty eye condition known as pink eye at some time or other. It's the most common eye problem children have.

The medical name for the condition is conjunctivitis. It's often a side effect of winter colds, but pink eye can be a summer problem, too.

"Swimming pools, hay fever and allergies, as well as colds, can trigger summertime cases of conjunctivitis," says Dr. Robert Petersen, an eye doctor at Children's Hospital in Boston.

When you get pink eye, the moist inner lining of your eyelid and the whites of your eyes -- the conjunctiva -- swell up and turn bright pink. Your eyes also produce a yellowish stuff that may cause your eyelids to stick together when you first wake up. Your eyes burn and itch. Pink eye is pretty icky. Luckily, it doesn't do serious damage to your eyes. But it is uncomfortable.

Summer pink eye is usually caused by the chlorine that used to keep swimming-pool water free of germs. Chlorine does a good job of keeping water clean, but it's a strong chemical and irritates the delicate tissues of your eyes.

After swimming, your eyes may look bright red and feel scratchy or sandy. Dr. Petersen recommends keeping your eyes closed or wearing goggles when you swim in chlorinated water.

The pink eye you get from chlorine doesn't usually need treatment. Placing pads of cloth that have been soaked in cold water over your eyes can help.

The redness should go away pretty quickly. It's a good idea to stay out of the water until the irritation fades.

"If the eyes are extremely red and uncomfortable, or if the symptoms persist, see an ophthalmologist," says Dr. Petersen. An ophthalmologist is a doctor who specializes in eye care.

So too much chlorine can be a problem. But too little chlorine can also cause pink eye. A pool without enough chlorine in the water may become polluted with viruses, bacteria and other invisible germs. These germs can cause an infection that reddens the eyes and creates a thin, watery discharge.

This kind of infection should be treated by an eye doctor. The patient may get medicine to take, eye drops to apply or eye cream to put on the swollen lids.

You might think that if you stay out of the swimming pool, you're safe from summer pink eye. Unfortunately, some kids also get the condition from hay fever.

The pollen from plants and flowers -- especially ragweed, which peaks in late summer -- causes sneezing, runny noses and itchy, watery eyes with swollen eyelids in allergic people. The medicine that allergic people take to control hay fever gets rid of the eye symptoms, too.

Allergic conjunctivitis and the redness caused by chlorine are not contagious. But pink eye caused by germs is extremely catching. Here's how it spreads.

Let's say you have a pink eye infection. You touch your eyes, and then later you touch a friend or a family member's hand. That person touches his eyes -- and bingo, the germs get into his sensitive eyes. Then he touches his eyes, and touches someone else's hand . . . you get the picture. Soon the whole family, or everyone in your cabin at camp, has pink eye.

Pink eye germs can also be spread by sharing the towels and wash cloths you use, or by sleeping on someone else's pillow.

If you have the contagious kind of pink eye, try not to rub your eyes, and wash your hands often. And don't worry.

Once it's treated, the condition clears up fast. Tips for Parents

Summer pink eye is more annoying than it is serious. But parents should be aware of an uncommon but severe allergic form of the condition called vernal conjunctivitis. In response to a specific allergen, the conjunctiva become severely irritated, causing tiny bumps to form along the membrane and around the cornea.

"In some children, the eye is especially sensitive to certain allergens that are absorbed directly by the conjunctiva, causing irritation," explains Robert Petersen, MD, director of the Ophthalmology Clinic at Children's Hospital, Boston, Mass. Symptoms include itchy eyes and a stringy, white mucous. The condition should be treated by an ophthalmologist, who may prescribe hydrocortisone drops. Catherine O'Neill is a free-lance children's writer in Batimore.