A person may require the use of a magnifier if they can not see the task at hand even with visual correction (spectacles).
Some eye diseases such a macula degeneration cause damage to the retina. Small objects can no longer be seen. So in order to see them the person needs to make the object bigger.
You can either bring something closer to make it bigger; or you can use electronic tools such as your Ipad to take a photo and zoom in; or use a magnifier to make the image larger.
You might even just have a hobby with small details that you need a little bit of extra help to see.
It would be best to come in and discuss your specific needs to see if we can come to a solution together.