Good question. If you want to buy reading glasses for vision aids, first of all, you need to visit an eye doctor and take a detail eye test. Although it is costs, this is the only way to let you know your eye prescription that is very important to buy reading glasses. Then, you can take your prescription prescribed by eye doctor for ordering reading glasses. To saving money, you can try to get good quality reading glasses in low prices from online optical shop like Firmoo.com.
The best way is to see an eye doctor and have an eye exam. Then you can get your correct prescription for your reading glasses. If you have the same power in both eyes and have no other vision problems, you can copy your prescription and get your reading glasses from the drug store which offer cheap reading glasses. If you have diffrent power in both eyes, you either get your reading glasses from your eye doctor or get them online with your prescription.
Here are some tips to help you know What strength reading glasses you need 1. Consider going to an optometrist or ophthalmologist to get prescription reading glasses. Most people require slightly different lenses for each eye. Over-the-counter reading glasses do not correct for eye differences or common vision problems such as astigmatism. These one-size-fits-all lenses can cause eyestrain and even headaches. 2.Pick out a pair of glasses at a strength you think might be right. Reading glasses in pharmacies are usually sorted by strength. Don't worry about finding a pair you like yet--as long as it fits you reasonably well, it will do for the moment. 3. Get a magazine from the magazine rack or a book from the checkout aisle and hold it the way you usually do when you read. If you like to read lying in bed with your book right in your face, for example, hold it right in your face. Try reading it and notice if the words are blurry. 4.Try on a stronger pair of reading glasses. Are they better or worse than the first pair? If they are better, try on an even stronger pair. If they are worse, try on a weaker pair. For example, if your first reading glasses had a strength of 1.00, try 1.25 glasses. If they work even better, try 1.50. Keep trying on new glasses until you find the best strength for you. 5.Once you find the right strength of reading glasses, pick out a style you like. Reading glasses come in full-frame styles, which cover your whole field of vision, and half-frame ones, which only cover the bottom. Full-frame are great for looking at things very close up, but they don't let you look into the distance clearly. If you are going to be switching your focus between near and far objects, get the half-frame glasses. If you are only going to be concentrating on what is right in front of your nose, use full-frame ones. Read more: How to Know What Strength Reading Glasses You Need | eHow.com http://www.ehow.com/how_4777287_strength-reading-glasses-need.html#ixzz1ynYQFhL7
Go to pharmacies to select a pair of reading glasses at a strength you think might be right. Then wear them and hold a book or a magazine in a hand at the distance you usually do. Next, read the words through your reading glasses lenses. If you can see words well with no discomfort, then the strength might be correct for your reading glasses. If you can't see well with that strength of reading glasses, you should choose another pair of stronger or weaker reading glasses to try them on and see what strength of reading glasses are suitable for your eyes.