Refractive lens replacement surgery

My 85 old father had cataracts. The wait on the NHS was long. We paid to go to a well known clinic . Dad had mild dementia, I felt he would get more attention in the private hospital . Anyway the op was done and we were told it had not worked because of macular degeneration. We felt totally ripped off because it had not been diagnosed before the op.
Obviously this is just one case but I felt it had just been done for the money . My point is make sure your doctor doesn’t just want to operate on you for their own benefit financially