Go and get just an eye test done. Get a copy of the prescription (they are obliged to give it to you and will probably do so without you even asking).
Go home and go to
If you want a pair of prescription magnifying glasses for detailed DIY then look at your prescription - it will probably say "add xx" where xx will probably be a fairly low figure. Order a pair of reading glasses and on the order form substitute the maximum figure in the "Add" box (+3.75) for the prescription figure. You will get a pair of glasses to your prescription with a focal length of about 12"
- ideal for precision work.
optical4less.com seem to have a very good reputation and reliable service. SWMBO who has a very complicated prescription has saved a considerable sum over three years of using them.