Even if you've always enjoyed perfect vision, it will probably come a time (about 40 years), when you need a prescription reading glasses. As we age, the lenses of the eyes are less flexible, which means it is harder to read materials that are close. Of course, you can adjust to some extent at first holding reading material further away from the eyes, but in the end, it will come a time when you will simply need to get reading glasses.
What is "off the shelf" non-prescription reading glasses?
Even though you can get a drugstore "reading glasses", without a prescription, it is best for the health of your eyes, in general, go to your doctor, get eye exams, glasses and get a specially tailored for you. This is necessary for several reasons. Number one, even if you have perfect vision, it's a good idea to see your doctor every few years to ensure the health of your eyes is still good.
A second, even though you're sure to find a "shelf" a pair of reading glasses that you see when you read properly, prescription glasses are generally better because they are tailored just for you. That means less strain on the eyes. It May also be advantageous, because you will not have a headache (literally) from wearing these glasses, as opposed to some "off the shelf" spectacles may be purchased that are not quite right.
Start "reading glasses", if you already wear glasses because of myopia
If you already wear glasses, because you are nearsighted, you'll need to switch from a single vision lens bifocals. These glasses let you focus on the distance, as always, and then give a specific prescription parameters at the bottom of the lens for close reading material.
What kind of specs would you choose?
If your vision is fine for viewing distance, you May be OK with just getting the glasses that you keep in your pocket or purse for reading purposes. These glasses can be full or half lenses, and it was nice. They just look different. With a full lens, the lower half of the lens is set with a recipe that will allow you to read things up close, and then the top half of the lens simply glass or plastic, without a prescription.
There are also "half-lens' prescription reading glasses, similar to the one you saw Benjamin Franklin carries the portraits and views. These glasses are very small, literally 'half-lens "in size. They allow the wearer to "look down" through the lens for close reading material, and then simply look at the top of small lenses for distance vision.
Regardless, remember that getting a prescription for reading glasses may not be a problem. It simply means that you need a little extra help when you read, and it would be easy to get.