Here's a few suggestions. Remove the ficus tree and replace it with another non-toxic tree. Although ficus's are normally great to have, if the branch is broken and sap leaks out, it can cause eye irritations. Hibiscus plants are great and they love the flowers, but you should do your research on cham sites or melissa kaplans site to find out if that could cause the same problem. I kept chams for years, but it's been quite awhile and I'm sure there's more info available.
Another thing. Chameleons are very sensitive to supplementation. And usually the first sign of a problem is with the eyes. Either they start closing 1 or both, or the eyes start swelling or are more prone to infections.
The best thing to do is establish a relationship with an experienced exotic vet. Usually before the cham gets sick so he sees him healthy and can identify changes in appearance when sick. If your not able to do that, go over your supplementation regime with other experienced cham people.
Chameleons do better when fed bugs that have a better quality gutload, and not as much supplementation on the side. Variety is important. Let this thread know your supplement regime as well as any gutloads you use.
Last, you should have a thermometer to let you know if the temps are varying. Some places, like where [i] live, I have to up the wattage in January, and lower it in June.
It looks like a great set-up. So go with these ideas;
1. Change the ficus for hibiscus (I don't think umbrella plant is problem) You can put ficus next to cage to provide privacy.
2. Join a few different chameleon email groups that may have a few exotic vets. I know one, [i]'ll ask what groups he's on. They're very kind and willing to go over problems long distance.
3. Tell us what kind of supplementation and schedule, as well as any gutloading.
4. Tell us your temps in cage as well as outside.
5. I'd sterilize the cage incase he's getting the beginning of an eye infection. Often sitting them in a tree in the tub, with the shower on, but not directly under flow, to steam the bathroom up and hydrate him helps, but you can't leave him alone because he can fall or drown.
Check out these links, and if they don't google them;
(Adcham is my favorite)..
Click here: Welcome to ADCHAM
Click here: Edward I
(Edward Pollack dvm?)
Hope that helps!