I don't know about the flying side, but following a PVD, I had a sudden onset cataract which caused quite a few problems as it matured. Mine was in the centre and triggered multi-lensing - the brain trying to see round it, switching between possible routes. Very disorientating.
I was told that where you have it done can be chalk and cheese, some people having the need for substantial correction after the op. I had mine done in Texas and was disappointed to find that to get 20/20 I needed specs, but it seems that I was very lucky in comparison to some folk, the correction is very small, and most times I can do without correction.
So, researching just who will do this, and putting pressure on to get an accurate prescription is, I think, important.
(I was unable to have free medicine in the UK due to being out of the country too much - they obviously needed to save the money for people that have never paid into the system)
