Q. Wearing (carrying) glasses on Shabbat in Reshus Harabim vs hearing aides w/batteries both medical. Are both they allowed?

A. Wearing prescription glasses when needed is permitted in a Reshus harabim. Hearing aids for people who need them critically (as in hearing the incoming traffic on the street) are permitted when turned on before Shabbos. It is preferable to use hearing aids that fit snugly in the ear and are constantly used and seldom removed. Hearing aids that are part of glasses are permitted as above (Rav Shlomo Z. Auerbach Zt”l quoted in Shmirat Shabbos 32-28 and Rav Shlomo Miller Shlit”a.

From Rabbi a. Bartfeld – Ask The Rabbi – Frum Toronto