We can go all the way back to the eyespot and demonstrate scientifically how the eye originated. The problem is that we cannot find a single strong hypothesis of why the eyespot came into being in the first place. This is a dilemma that has plagued evolutionists and that has surprisingly been underutilized by creationists.
As we discussed in The Unaddressed Evolutionary Challenge of the Eye’s Origins:
To generate the evolutionary need for creatures to detect light and therefore develop photo-sensitive cells, they would have needed to understand that light existed in the first place. With nothing to let them know that light existed, there would have been no need for photo-receptors to evolve in the first place. Eyespots are the earliest stage of the evolution of the eye. You can trace it all back to eyespots. However, there is no explanation for why eyespots came into being.