You can give him saline drops to flush it out. I tried Veterycin opthalmic gel on one of my drakes 3X/day. It didn't do anything, so after several days of that, I mixed up a few drops of natural honey a friend had given me and some rosewater (an ice cube of it) I had in the freezer. (It was a recipe I found online intended for human use.) After a day and a half his eyes stopped foaming and crusting over, so I put him back out with his buddies. No more problem.