There are several subspecies of eyebright (Euphrasia nemorosa) but the differences between them are microscopic so it is in order, I think, to lump them together as 'eyebright'.
They are tiny flowers, easily passed by without a second look, and one where the close up camera lens reveals an almost hidden beauty inside those tiny flowers.
It is quite common on grassland, downs, heaths and open woodland where the vegetation is fairly shortly cropped; the sort of habitat that one frequently encounters in Dorset and so this is quite a common plant in the county.
I believe it gets its name from the fact that it was (is?) used to make drops to sooth sore eyes and keep them looking fresh and, yes, bright! Maybe, if you find it, you should get down and have a close look as it is obviously a sight for sore eyes ... I'll get my coat!