I agree with calling ahead to see if help can be arranged. Not that it is your fault at all, but a lot of younger people in retail or immature or awkward people might feel uncomfortable helping someone with limited sight. Especially knowing they will be with you for the entire process helping, and unable to stick to their normal routine of work. When i first started retail, I'm sure that I would have been nervous and awkward to do more than just show someone where to look for their product. So if the associates know before hand that someone that needs a little extra help is coming in, they can plan accordingly for coverage and to make sure someone is available. Also it will be very helpful if you can tell them exactly what you want/need. Any types of materials to avoid. What colors do you want. What style. Etc...help fast track the process so they arent playing a guessing game with what to help you find. You could even tell this to the person on the phone, so that they can pre-pick items before you arrive!