The 26-year-old stopper even believes the first time he wore them in a match last month was the biggest victory of the entire season for him.
He recalled: "I had been complaining about not seeing well since October. It came to a head against Arsenal.
"I thought I had the ball in my hands and then suddenly it flew past me. That had never happened to me before. I couldn't explain it.
"It seemed I was getting in position a bit later than I normally would or that I was reacting a little bit more slowly."
He was on the brink of a return in early April only to suffer a training-ground injury when he needed 50 stitches in a facial wound following a collision with Tal Ben Haim.
He added: "Together with the goalkeeping coach I studied footage from last season and this season in terms of how I dealt with crosses and situations.
"You could see a huge difference in the way I moved. After I got injured, I had enough time to go for various check-ups.
"In the end I got contact lenses and now I can see 100 per cent better. So it's possible to find positives out of the injuries."
The Blues No 1 added: "I have to admit the first day I was supposed to wear them, I got up an hour and a half earlier than usual. I managed it somehow.
"When I tried the lenses for the first time, I realised what a big difference they made. Getting them was possibly the best moment of the season for me."