[Euphrasia officinalis]
The aerial (above ground) parts of the plant are used. As its name suggests, it helps eye problems by relieving inflammation and tightening mucous membranes and is specifically used in treating conjunctivitis and blepharitis. Used for infections and allergic conditions affecting the eyes, middle ear, sinuses and nasal passages. 

Recommended dosage 1/2 Cup daily per 500kg horse