Below you will find information about managing specific health issues with your chameleon where we feel confident in the advice rendered.  All of the advice was determined here after years of experience, and every bit of it was developed working with one or more of the top chameleon veterinarians in the country.

This will be a work in progress for a long time.  What you will see immediately below is a list of the topics addressed, in numerical order.  You will then have to scroll down to that section which interests you, as some segments are quite long.

We do not want to discourage taking any ill chameleon to see a vet.  However, we would suggest seeking out as much info as you can in the time available prior, as many vets, although meaning well, still lack practical experience with chameleons.  Again, everything posted below was determined in conjunction with some of the top veterinarians in the country.  

1) Scratchy eyes: My chameleon was healthy, but now is rubbing one eye.  Doesn't keep it open well.  See Vitamin A deficiency, #1 

2) Mucous mouth.  If more advanced, then breathing issues.  Making popping noises at times.  See Upper Esophageal Infections, #2
1)  Possible Vitamin A Deficiency in Panther Chameleons, Symptoms and              Solutions

Vitamin A deficiency is a common malady in LTC (Long-Term-Captive) Panther chameleons, either with WC (Wild Caught) or CB (Captive Born) origins. This stems from the chameleon's inability to synthesize real Vitamin A from common precursors, such as beta-carotene. This can be confusing when evaluating supplements, as many dry supplements list Vitamin A content, but only as the precursor, beta-carotene, and not as “pre-formed”, or in essence, real Vitamin A.

While lack of Vitamin A effects many aspects of chameleon health, the usual first observed symptom is the appearance of an unexplained eye irritation, manifested in difficulties in keeping first one eye open, and after a few days, both eyes are affected. In most cases, the eyes will not appear sunken, or in any other way mis-shaped initially, although secondary problems, such as an infection, can follow. The usual initial observation is that it is causing irritation to the chameleon, and that it can't keep the eye open as normal. It occurs more often in larger animals, but sometimes occurs in larger juveniles. In select cases the eye may appear as swollen. Successfully hatched chameleons seem to be born with a supply of Vitamin A, an essential ingredient for successful embryonic development, and fresh WC’s seem to be imported with a supply. Mother Nature seems able to provide this vitamin without problem. Without some real vitamin A in their diet, these stores will deplete. It is a difficult vitamin for the hobbyist to gut-load via crickets and insects though, and such attempts are usually ineffective in our experience.

Vitamin A is a fat soluble vitamin, as is Vitamin E. It is most commonly sold in gel caps, with each gel cap containing approximately three drops of an oil solvent. It is available on-line from many suppliers, or is sold in most vitamin and health stores. The most common, and consensus most effective form of vitamin A, is a compound known as retinal palmitate. It is a common human food supplement as well. Depending on manufacturer, gel caps may contain 2000-25,000 iu’s (intravenous units) per gel cap. Read the label to insure you are buying a product with retinal palmitate as the Vitamin A. The solvent may be fish oil, which outside of its odor, is OK.

You can usually find an adequate source at such as a GNC store. When looking online, here’s a link:
However, if the link has expired, google “Vitamin A Carlson Laboratories” and you should find many product options.

One other form of Vitamin A can also be available as the compound retinal acetate, which is synthetically produced vitamin A. While not as effective as retinal palmitate, the acetate version is more easily crystalized, and then included in some dry products, such as the ZooMed vitamin powder marketed as Reptivite.

Vitamin A is toxic in large quantities. As you are dealing with an oil, a strong word of caution as well. Chameleons have an extreme dislike for almost any measurable quantity of oil introduced into their mouth. While inexact, usually a negative reaction starts to become likely to occur if a quantity of oil ½ drop or greater is introduced into an adult chameleon’s mouth, and is virtually guaranteed with 2 or more drops. This can induce vomiting and inhalation of the oil, possibly death. Fortunately, the amount of oil (and vitamin A) needed to effectively dose a chameleon is usually less than 1/20th of a drop. Again, an inexact science, but depending upon the concentration of the Vitamin A in the oil, your goal is to deliver a dose that contains approximately 100 iu’s per 50g of chameleon. An exceedingly rough estimate would be 1/20th of a drop of the oil in an average adult female panther chameleon. There is a reasonable margin for error. This can administered by puncturing one or more gel caps, and wetting a Q-tip with the oil, so that is is wet, but not dripping. You can then grab the chameleon behind the head, and when it says “Ahhhh”, touch the Q-tip to its inner gum, etc. It will likely chomp down, then let go of the Q-tip once released itself. Or, if you are able to hand-feed, swab the back of a cricket or such with a smear of the oil, and then coax your chameleon into eating it.

As a rule, we recommend this treatment to all adult chameleons once every two weeks. If an animal is showing symptoms of Vitamin A deficiency, such as eye closing with no other apparent malady, we recommend the dose daily for five days, then once every two weeks. In such cases where Vitamin A deficiency is the problem, and it is caught early, the eyes usually improve on the third or fourth day. In animals where treatment has been delayed, improvement can take up to 2-3 weeks, except in cases where the treatment has been delayed too long and become beyond repair. 

The above criteria were developed working closely with Dr. Ivan Alfonso, an Orlando area verterinarian with considerable experience in chameleons.  Further support for our findings can be found at this link, where Dr Gary Ferguson relates his experiences with this issue :

2) Upper Esophageal Infections (Contaminated 'Poison Pill' Insects)

Upper E. infections are indicated by a build-up of excess mucous in the mouth and upper throat areas, and is indicative of an underlying bacteria infection there. It is not caused by excessive or extreme temperature/humidity fluctuations, as similar appearing infections in other reptiles are, and which are often respiratory in nature. Rather, it is most often caused by the introduction of large quantities of otherwise common bacteria into the chameleon's mouth via its food, most commonly scavenger insects, such as crickets. These insects have been raised/exposed to poor insect husbandry conditions, which created a high bacteria source in their food/water, which they then ingest, only to unload into the chameleon's mouth once chomped on. The insect has become a "poison pill". The cricket can handle the high bacteria count it has ingested into its gut. Your chameleon cannot handle the same into its mouth.

Let's assume crickets. What has happened is that the cricket is ingesting from a bacteria stew somewhere. This may be wherever you house your crickets, or where the entity that you purchased them from did, or it may be right in your chameleon cage. If in a cricket bin, any water source that is not removed and disinfected at least once every two days becomes a source of high-bacteria. While temperature variant, and many crickets are raised at higher temperatures so that they grow more quickly, if not cleaned/disinfected every four days, contamination is almost a guarantee. Crickets will foul their water supply, no matter what or where it is, and then the bacteria will multiply exponentially. These sources include such as the cricket water bites and gels, sponge waterers, etc. Whatever the means, it should be washed clean every two days. You will never eliminate all bacteria, and that is not the goal. If in doubt, hold that water source to your nose. If it stinks, and it will, then it has sat too long. Gels etc can be easily removed and rinsed clean. Clean and dry the area where the moisture gels are presented, and you are good-to-go. If sponges, clean them with detergent and water, and rinse well. Again, you are not ridding anything of bacteria completely. Just getting it back to the normal parameters in which we all manage quite fine.

As mentioned above, the contamination can be happening in the chameleon cage. Many folks use live plants with a water dish beneath it. If there is standing water in that dish, or some other source of standing water in the cage, such as a fountain, or an area always wet due to a mister, etc., then crickets will foul that once in the cage, while also drinking from it. So you have to clean those things as well. Slightly moist dirt is OK. These levels of contamination require such as standing water, a wet sponge, mud, gelatins, etc.  
If you are buying crickets from any supplier, expect them to be contaminated as well, as most cricket breeders have highly contaminated watering systems. For instnace, they will use large 1 gallon sponge-bottom waterers, changing weekly at best. The crickets can handle it, and to change them more often is deemed unnecessary work by the cricket producer/seller.

Symptoms are a visual build-up of mucous in the chameleon's mouth. While a chameleon's mouth is always moist, it should not have obvious mucous. As it worsens, it may start to dribble from the chameleon's mouth, and/or become a crust on the outer lip. At the same time, it is heading for the lungs, and will eventually become a respiratory infection. If identified early, and the contamination rectified, it may clear on its own. Once into the lungs, it most certainly will not. This process of advancing infection may take a couple weeks or more. Fortunately, it is easily diagnosed, and if antibiotics are needed, easily cured. Unfortunately, the cost of the vet visit will be the basic visit ($25-40), the bacteria panel ($75-100), and the antibiotic ($15-30). And you will have to locate, and eliminate, the contamination source.

It is our experience that this malady is common in captive chameleons. Unfortunately, it is not diagnosed until it has become an Upper Respiratory Infection (URI), which while it can then be addressed with antibiotics, does not address the original cause. As such, this husbandry lapse can occur over and over.
Our findings here came after months of research, and considerable expense, at our Florida facility in 2003, working with Dr Ivan Alfonso, one of the most experienced herp vets in the state of Florida.