Hey,
First of all, a pic would be great. Here are the probable things it is:
1.) Something is stuck in her eye- if this is the case, when she opens her eye (10% of the time) look to see if you can see anything. If you do, DO NOT TOUCH IT!!! Simply put her on a plant, put the plant in the shower, and set it to luke warm water on a very fine spray, or adjust it so that it is pointing at the side of the tub and sprays off onto the plant. Leave her there for a few hours.
2.) Respritory infection- This is the most likely cause. This is normally caused from having the chameleon constantly breathing stagnant air, i.e. having him in a tank or having very poor ventilation. Put him in a screen cage to prevent this prob from happening again. You will have to bring him to the vet for this. If she does have this, she will have very thisck saliva and even bubbles in the back of her throat. Open her mouth and take a look.
3.) Parasites- I don't have time to discuss the different types of reptile parasites, causes and treatments right now. However, this is a definite possibility. Simply wait for your animal to deficate and bring it to the vet within the next few hours (within 24 hours I believe). He will examine it under a microscope and perscribe meds from there.
Eyes are ussually the first sign that a chameleon has a problem. Chances are it had a problem for a long time without you knowing. Animals don't show signs when they first get sick. If they did, the predators would know to catch them first cause they are an easy catch. They do not show signs until they are far along, and the sickness has manifested throughout the chameleons body for a while. You will have to bring it to a vet either way. Find a vet that will deal with exotics, ask him if he has any experience with chameleons, and after calling a bunch, pic the best and schedule an appointment ASAP!!!
Well, why are you still reading this thing!!! Go find a vet!!!
Ank-Inc.
Adam.