I can definitely say I have developed a fear of heights since my surgery, and I have a theory as to why. Heights make me dizzy, because with 1 less set of vestibular canals to work with my vision is much more important for my balance. If I am standing in a room in my house, and I move my head to the left one inch, I can see my surroundings move accordingly. However, if I were standing on top of a 100 foot cliff looking out over the edge, when I move my head slightly I won't be able to detect any difference in my surroundings. I get the same effect if I look up into the sky or if it is completely dark.
So for me, having less of a close visual reference really messes with my ability to balance and therefore I like to keep my feet firmly planted on solid ground. Maybe this could explain why heights bother you more now too.