After shrapnel severed the optic nerve in my right eye, shrapnel made hamburger out of my left eye also. After 20 years, I had cataract surgery which took 6 1/2 hours and an overnight stay at the San Francisco VA Hospital, but my eye is FUBAR, so a normal procedure is a 1-2 hours, I can see much better. I still need to wear glasses, get major migraines, and my eye hurts constantly.
Again, my situation is far from the normal routine, but I wouldn't sweat it. Get it done, and then enjoy your new vision.