I agree with you that the NHS provides some good things and for a routine or otherwise well known illness I have found the NHS to do a good job.
However, when you have a unusual condition, as I apparently do, and which standard testing doesn't reveal any insight into, then you can be basically ignored by the NHS until your condition becomes debilitating. Unfortunately, by that time, it's generally too late to do something about it.
I have no real idea why the consultants will not spend any extra time trying to track down the problem, but I suspect it has to do with the NHS been very target driven and getting people through the door as quickly as possible. To any NHS workers here, I am sorry if that seems harsh, but it's how I currently feel.
The opinion of this patient is that the NHS needs to develop procedures for been able to spend time diagnosing patients with unusual conditions and not leaving it until it's too late to do any good about it, because right now, my only real hope is that this condition (whatever it is) stabilises before my vision gets too dim to be of use.
(BTW Slashdot, if anyone here has any ideas about why a person's perceived brightness level would dim without any MRI or VEP tests been positive, I would be very interested in any suggestions you may have.)