The same sort of sensation was happening to Phaedra.
Her brain, her vampire brain, knew that the dress was green. It knew. But her eyes refused to see it that way. Slowly she adjusted; first it was greener shades of gray, then simply a dark, deep gray.
It was very frustrating. She looked around the room, trying to figure out in vain what color everyone's actual clothing was.
She watched the exchange between The Doctor and the girl without reacting. She simply shook her head when the question was asked.