I have to disagree about putting down opticians. I have had eye problems for months and have seen a proper NHS eye doctor. He has been about as much use as a spare trick at a magicians wedding. The optician not only diagnosed the beginnings of a cataract missed by the doctor but also deducted my problems are related to fluctuating blood sugar levels. Admittedly they can only refer to those who can do something, but at least I know what is wrong.