I think that bubble is the reason they get drop eye. that is where the fat deposit builds up that causes it. My last silver had drop eye in one eye and that bubble would get bigger and small all the time and make the drop eye appear better and worse. funny thing and it might be a fluke but it would always be worse right before I did a waterchange.. I don't know if that helps but it's all I got.. aro looks great though DeL.