Prior to cataract surgery, my near-sighted vision was near perfect; I could read without glasses. The surgeon implanted lenses with the same power as my natural lens. But one eye is slightly off by -.50 to -.75. Should I have the lens replaced?
There are really two issues here: 1) Why is it, to your surprise, you now need reading glasses and you didn't before your cataract surgery? 2) How easy and safe is it to remove and replace an intraocular lens (IOL)?
Nearsighted (myopic) people enjoy one single advantage over other, normally sighted people: For the same reason they cannot see off at a distance without glasses, their default focal point is at near. This means they do not have to accommodate, i.e. use the muscle surrounding their natural lens to squeeze it into a different shape better suited for near vision. When people become presbyopic in middle age, it is due to the natural lens hardening which creates resistance to the muscle. But since a nearsighted eye doesn't need to accommodate to see up close, you can still read (at least without your distance glasses on). As the natural lens ages further, it slowly discolors and becomes hazy. That is the cataract.
_Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic