How to map CTRL + scroll to OPT + scroll

I use the shortcut OPT + scroll (mouse wheel) all the time to zoom in/out when working on graphics and video editing, but I keep accidentally hitting CTRL instead, which does nothing so the document scrolls up/down rather than zooming. I want to make CTRL be the same modifier as OPT when scrolling with the mouse wheel, but I can't figure out how to configure this. Note that I have disabled the CTRL+scroll accessibility gesture that causes the whole display to zoom—I only want the document in the current application to scroll.

Can anyone help?