Ann: Optiscan Intends to pursue De Novo Pathway for InVivage, page-42

They consulted the FDA first remember and followed what they believed was correct advice.
Now it might be the change in the contrast for the trial wasn't mentioned at the time or changed after the consultation or it's significance wasn't appreciated. They did however go through a significant validation process over use of the alternative dye to make sure it met FDA dosing and safety requirements.

But there it is. Presumably if someone had said "but we aren't going to use fluorescein as the contrast for the oral cancer trial submission evidence, is that still OK with you?" the FDA would have said hang on, I'll check... NO".
But the FDA only respond to specific questions, they don't design the trials for you. The company isn't the first one to get tripped up, and no doubt someone somewhere in the company made a fatal decision or overlooked something. It happens quite a lot, we're human.

So we need to go back and resubmit on the new forms.