Take a piece of a sample you have that is sewn together or a piece of clothing such as from jeans or? Take that to a store where you know they have glasses on display. Or if you go to Wallyworld or a office supply store. They may have what you're looking for. My own ophthalmologist suggested I could get them just as inexpensive as he could prescribe. Just try them on. Last time I purchased a set of 4. They work for the computer and sewing/ripping. There are some seam rippers that have magnifying glass on the end also.