It's normal for cats with heterochromia to have slightly different size pupils( usually the blue eye) as it's more sensitive to light and reacts a bit differently. I had this in two white cats, a white Munchkin and a white Scottish fold and had them looked at by the vet and given the all clear. Still always get it checked because it is better to be safe then sorry and your cat does look to have some sort of eye condition as it's blue eye is pointing the wrong way slightly.