In reply to Rob Exile Ward:
Yes, the DVLA have the final say. Realistically, if someone misses no points, then I can't see any reason why an optom can't say "you're fine (inform the DVLA of your results)", similarly, if there's a whopping great defect nudging right up to fixation then it's a clear duty of care to say "please, please do not even think about driving, in my professional opinion you are absolutely not safe, nor anywhere remotely close". In the in between cases, it would indeed be wrong to second-guess the DVLA decision, but the info in the link I posted is published and provides a good guide to the likely outcome; as such it would be sensible for the patient to behave (i.e. drive or not drive) accordingly. But in that kind of case, I would probably be prudent to get on the phone to the legal guys before I opened my mouth.