As the name implies, bifocal glasses has two focus to help you read and watch TV at one pair of glasses. In order to use the glasses properly, first of all, you shall check up the segment for close-up vision correction. Usually, there is a visible line in the mid of lenses that to separate the lenses into two part. And usually, the lower part of lenses are use for reading, while the upper part of lenses are use for watching TV.
The bifocal reading glasses should sit high on your nose so that you don't have to slip the reading glasses up or down to see properly.
Make sure the bifocal reading glasses make you feel comfortable when you wear them. Next, you should find the correct part of the bifocal lens for close-up vision correction, which maybe the bottom half of the lens. Then look straight ahead through the top half of the lens which is for distant vision to see whether you can see clearly without problems. If you wear them in a correct way, you just take time to get used to them.