The best way to determine the correct strength, known as a diopter, is to have an eye exam. If you do want to select a strength on your own, start by selecting a low strength first and work your up from there.
You should be able to see printed material clearly at a distance of about 14 inches from your eyes. If the print is not clear, you can increase the strength in .25 increments until it is clear in the 14 inch range. The important thing is to stop when the print becomes clear and not use too much magnification.
Also, remember that the stronger the lens strength, the closer the focal point. For example, if the print is clear but you are holding the print further than 14 inches, you need to go a little stronger.
Ok, so we determined why we need them and what strength we need, now for many the most important aspect of choosing reading glasses is how they look when wearing them. Let's face it, they can make or break a look and people are going to notice.
There are 3 main keys to keep in mind when choosing the right glasses for your face:
1. The frame shape should contrast with your face shape as shown below
2. Frame size should be in scale with your face size
Keep in mind that a frame's size can effect how your face is perceived. For example, putting a small frame on a large face will make the face look even larger, and vice versa.
3. The frames should repeat your best feature
An example of this would be selecting a blue frame to match your blue eyes. Your best features can be the colour or tone of your skin, hair, or even your wardrobe.