One of two things is happening in this picture. He is possibly dehydrated and changes should be made to increase his hydration, longer mistings, running a dripper etc. OR he doesn't like having his picture taken and is pulling in his eye.
Have a another look at him when he is relaxed to be sure.
A shower as mentioned above is aways a nice idea for eye hygiene either way. Info on hydration and how to give a shower https://www.chameleonforums.com/care/water/
Please fill out the how to ask for help form below...the most detail you can give us will make sure we can help you with any changes that need to be made to your husbandry to give your cham the best care. Welcome to the forum.