When you are going to select a pair on your own reading glasses, you must pay attention to this. If your reading glasses are too weak, you may need to hold the reading material far away. If your reading glasses are too strong, you may need to hold it uncomfortably close to your face. So you must make sure that you can receive a correct prescription. When you are going to select a pair of reading glasses, you also need to consider what you will use them for.
I think first you should to know that whether you got presbyopia or not, if you really lost the ability to focus on objects close up, then you may need to buy a pair of reading glasses. Before buying them, you need to have you eyesight checked by an optometrist. Then you can choose reading glasses in the physical shops or online stores. There are also free glasses online, if you have any interest, you can have a look first.
You should get your prescription from your eye doctor. You'll need them when buying your reading glasses. You'd better have your glasses processed with anti-radiation & UV coatings. They will protect your eyes from harmful lights.
Consider your eye sight prescription ,Which reading glasses to buy depends on the prescription that you have. A prescription is generally provided by an optometrist or an eye doctor at vision centers. It is a negative or positive number that you can use when choosing types of reading glasses, and consider the style what you suit for your face shape.