Why are reading glasses available to be purchased without a prescription?

[Isai]

I can't understand why reading glasses can be purchased without a prescription. How do they know it is suitable for their eyes?

[Samson]

Some people only need reading glasses without prescriptions because they have perfect vision and want to wear reading glasses for fashion. So in order to meet the need of these people,the reading glasses with non-prescription have been appearing on the market.

[Cassius]

There are non prescription reading glasses pre-made with same power in both lenses. Some people only have presbyopia without other vision problems. So they don't need a prescription to get reading glasses.

[Hezekiah]

People who only get presbyopia can get reading glasses without a prescription. My mom got a pair of reading glasses without a prescription from over the counter recently. And the reading glasses can help her see better while reading.