Eye problems are most often caused by dehydration, but they can occasionally get a bit of leaf or twig in the eye, scratch the eye on something, or get a bit of shed skin under the lid. Sometimes eye problems are caused by vitamin deficiencies, but be careful...vitamins are easy to overdose. Check your gutload to make sure it is good quality rather than start dosing the cham with "extra" vitamins. If there is sticky discharge from the eye or he can't open it because the lids tend to stick shut, this is a definite sign of an infection. You should have a vet check the eye for injury and prescribe the correct antibiotic. If there is no discharge or gummy matter on the lids and the pupil itself is clean, the showers and extra misting will help him clean it. You can also squirt sterile saline at the eye (contact lens rinse solution...it won't sting like plain water) to help him flush it. Check your cage humidity...it may be drying out faster and more than you realize especially during winter.