It's probably different with every snake, but with Pelota, here's how it goes:
Blue eyes for 5 days. On the 5th day her eyes clear up. 2 days later, she sheds.
She's like clockwork. All her sheds with me were just like that. Last shed, she started with blue eyes on friday, and by the next friday, at 9pm, exactly a week from finding her with blue eyes, she shed.