You should firstly make sure what you will use them for. If you need to wear them reading in the open air, you can choose sunglasses that can offer UV protection.
And folding reading glasses are a wonderful choice for people who are always on the go because they can be tucked into a shirt pocket or small purse.
If you always work before computers, there are computer reading glasses available which are quite welcomed nowadays because they are designed for a further reading distance and have the magnification area higher up.
Besides, you should also take the material, the frame, the color and the type of lens into account.
The reading glasses are usually used for people who are over 40 with presbyopia. When you select the reading glasses for your mother, you had better pay attention to the following factors. Firstly, you should clearly know the strength of your mother's prescription. So you had better take your mother to take an exam by the eye doctor. And you should also consider your mother's face shape, usually we choose the reading glasses shape that is opposite to our face shape. For example, if your mother has a round face, you don't choose a round shape reading glasses. And her job type is also considered as criteria, because the frame of the reading glasses can be designed based on different requirements, such as rimless, full-framed.
Firstly, you must do a optometry to decide the prescription of glasses and the eyes distance.
Second, try to choose the grey lenses which are helpful to protect your retina.
Third, wear the reading glasses, and then test if there are symptoms such as dizziness or feeling of the object deformation. If the symptoms above happen, you should change another glasses for adjustment.
The most important thing is that you should take your mother to the professional shop and have the optician to test for your mother. Both myopia and hyperopia need to the exact prescription. You should select a suitable and comfortable frame for her, plastic may better. Please don't forget that the frame is the lighter the better. As for the lenses, resin is the best choice. Of course, you should also ask your mother's opinion.