Buying contact lenses

Can you buy contact lenses without receipts in Japan?

Do you mean without prescriptions?

I've bought contact lenses without problem from Megane Store. The first time I just walked in with an empty package of my old lenses I'd brought with me, so that they would know the strength. There has been times when they don't have them available immediately though.

But on the other hand, when I once went to a different store (don't remember the name), and they insisted that I'd do a eye check-up with them before I could buy lenses. But as I happened to not bring my health insurance card that day, I declined.

Not sure about those from the optometrist/eye-wear shops, but you could easily get those coloured/non-coloured lenses with prescriptive power from Donki (Don Quixote) with no problems. No questions asked, no specialist proof needed. All you need is to fill in a form stating the degree of your lens and to sign an agreement that they're not responsible should anything happen to you.