It is definitely an option, the problem is that you may have a problem getting it covered by your insurance plan. It is a well known, legitimate way to correct a power problem after cataract surgery. My preference is usually to exchange the implant, especially if I can do it in the first month or so after the original surgery. If the original lens has been in for several months or years then exchange is harder and a piggyback lens is a more attractive option. Some well respected experts like piggyback lenses because they can get right to the problem as it is by adding or subtracting a certain amount of power to the eye by using a plus or minus lens in the ciliary sulcus. Disadvantages can include possible dislocation or poor centration of the piggyback lens and possible inflammation due to the implant rubbing against the iris or ciliary body. In general, Iike IOL exchange if I can get away with it in certain situations, piggyback lenses are an excellent choice also. Ask your surgeon why he favors his method and how much it will cost.
Thanks for the quick and detailed explanation to my questions. Advise well taken and this informaitons will help me and the surgon to go with the appropriate procedure.