"I just fell to my knees. I was blind. It was devastating."
Miss Powell had apparently been holidaying with friends and had been drinking party cocktails in the bay resort of Laganas, famous for its stretch of rowdy bars.
After the evening out she was said to be feeling normal, slept but then woke up unable to see.
Doctors on Zakynthos immediately transferred her to the hospital in the Peloponnese. It is understood she has made significant progress.
Her parents Christine and Derek Powell flew out from Middlesbrough to be with her as she led in intensive care in Patra.
Two of her friends that she was with on the trip also fell ill after drinking the cheap booze, although neither of their side effects were as severe.
Miss Powell had to have a kidney transplant from her mother, who fortunately was a match, to prevent her from having dialysis for the rest of her life.
She added: "My mum is my hero. Her transplant might be the lifeline I need for getting some kind of life back."
Drinks adulterated with cheap spirit, often home-made, to cut costs have been a consistent problem in the southern Mediterranean.
Spiked drinks, or bombes, are served in some bars and clubs in Athens and resorts known for partying - such as those on Zakynthos - have had problems in the past.
Dr Dimitris Goumenos, head of the Kidney Clinic at the University Hospital, Patra, said while she was in hospital: 'When she came in Hannah was on the verge of being blind.
"The problem was much more serious than just a plain methanol poisoning.
"Her parents wanted to take her home to Britain this weekend, but I would not be happy for her to travel on a plane until much later in the week, depending on her condition."
Zakynthos is the third largest Ionian island. It is popular with families and young couples, but Laganas has become a draw for students and young people keen to let their hair down, indulging in drunkenness and wild parties.