1. I always thought glass eye = blue eye - or is there a difference?
2. As you can see in the picture this filly has only partial blue eyes - in both eyes the lower half is blue, the upper half is brown. She is pure bred Quarter Horse, non of her siblings / close family shows any signs of an overo pattern. Her dam is home bred with many half and full siblings, her sire has two foal crops and none was noticably colored. Any idea what causes the partial blue eyes?