I just got an Australian Shepherd pup from a breeder. I thought the patch in his eye was marbling, but as i looked into it I'm pretty sure it's a coloboma. Does anyone have any experience with this? I've read mixed things about whether it's a problem. He does squint quite a bit in the sunlight, and he runs into things a lot but I'm not sure whether that's just him being an Aussie pup.