Why is there a need to insert a lens after a cataract surgery?
Because a "cataract" is the "age-related (usually), progressively dysfunctional natural lens of the eye." The word "cataract" is really just an old-fashioned word for this failing natural lens. When the dysfunctional lens is removed you must replace it with a new, artificial lens implant (IOL). If you don't (as was the case up to the 1970s) you would have to deal with the resulting lack of focus in the eye by using an extremely thick spectacle or contact lens afterwards. Historically, we once thought of a "cataract" as being a growth or haze that needed to be excised like a tumor. This conceptual framework keeps us from understanding what a cataract really is - the natural human lens that doesn't work properly anymore.
_Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic