Jan & Eli, while I deplore it, the fact is that the NHS is cash-limited. Much as I would like it not to be the case SOMEONE does have to make decisions based on the money they have available. The money has to be used for the best benefit of the greatest number - which is not to say I would not move hell & high water to try to get it if it were me in this position, but nevertheless there IS a limit to the cash available... This is precisely why NICE was instigated.
I don't know how much evidence there is for this eye op working, but if it is experimental it does not fall within 'clinical trials' criteria to allow it for one random patient.
My suggestion would be to persuade a medical business (BUPA or or a surgeon in private practice) to do the op as a 'pro bono' in the hope of (if a private surgeon, making a name for himself and) amassing enough evidence for it to become approved so they can make a lot of money doing it for other patients!

Boudi - a very good question.... - I guess it rather depends on what level of consent is granted in the first place!