Adult Male Cat... eyes turning brown. Please help!

He doesn't sit in his windows anymore.. and that was his favorite activity, I am really worried about him. I noticed it a few months ago, but just thought my eyes were playing tricks on me. Here are some photos- 



I already set up a vet appointment for him. Has anyone ever experienced this? 

I don't want to get his eyes removed!! I am so nervous for him..

It looks like he is getting cataracts this is normal unless he is young, this is an older person and older cat condition, how old is he? And it is good you are taking him to the vet.