Exposure therapy is fairly well studied: https://en.wikipedia.org/wiki/Exposure_therapy

I sometimes wear contact lenses. When I first started wearing them it took me over an hour to get them in. It was so hard to keep my eye open and put the lens in.

Over the weeks and months I slowly got better at it. Now I can literally touch my finger to my eyeball without flinching. The exact scientific reason for that, I don't know, but I did train my brain to stop reflexively closing my eyes when I go to touch them.

Without a lens on my finger touching my eye actually hurts a little -- so there is a good reason for that reflex in the first place.