euphrasy

n. [ NL. euphrasia, fr. Gr. e'yfrasi`a delight, fr. e'yfrai`nein to delight; e'y^ well + frh`n heart, mind: cf. LL. eufrasia, F. eufraise. ] (Bot.) The plant eyebright (Euphrasia officionalis), formerly regarded as beneficial in disorders of the eyes. [ 1913 Webster ]

Then purged with euphrasy and rue
The visual nerve, for he had much to see. Milton. [ 1913 Webster ]