Yes, your eyes will get bigger if you lose weight. There are fat stored in your face and cheek, when you lose weight, the fat will disappear as well. Then your cheekbones stuck out a lot and your face gets smaller. When your face gets smaller and defined, your eyes seem more bigger compared with they used to be.
Actually the eyes' size will not change even if you lose the weight. However, when you lose weight, your bones will show out. From the visual aspect, the eyes will look bigger. However, your eyes have no change in the actual size. But the slim people will show the big eyes because of the bones in the eyes.
It is very funny of the question. Losing weight is the whole life work of girls. I would like to say, yes! Your eyes will get bigger if you lose weight, especially lose a lot of weight! The more weight you lose, the bigger your eyes will be! Why? That is because your eyes are a reference object to your whole body. The bigger your body is the smaller eyes will be. The size of your eyes will be constant vs. your body's size will change. Moreover, some very ponderous people get with too much fat on his face, the excessive fat squeeze the space of the eyes; even make it into a small crack, that is a tragedy way to size the eyes. When you lose weight, the beautiful you will come appear! However, hope you keep healthy when you lose weight in a right way!