Has she shed recently? If so some shed could have got in it. Also do you have live plants in her enclosure? Some plants that are safe for chameleons can sometimes irritate their eyes if sap gets into it. Hopefully someone with more experience will comment and help you.
I had something similar happen with a female. This could be a sign of a serious illness as sadly my females condition deteriorated until she would not open either eye and stopped eating. I attempted medications per recommendations, but she passed shortly thereafter. My advice is seek veterinary assistance and keep her away from all other animals as this may be a bacterial infection or worse coccidia if it is not due to a foreign object or intensity of light. I wish you the best and if you need any further guidance don't hesitate to ask!
Thanks guys. Over the past couple days it's looked a little better. It will be closed in the morning but she will open it up and have it open pretty much all day. She's still active and eats and drinks and doesn't seem sick, but I'm keeping an eye on it