The healthy eye ought to see all visible things and not to say, I wish for green things; for this is the condition of a diseased eye.
Epictetus, Marcus Aurelius, Lucius Annaeus Seneca (2016). “Stoic Six Pack: Meditations of Marcus Aurelius, Golden Sayings, Fragments and Discourses of Epictetus, Letters from a Stoic and The Enchiridion”, p.116, Enhanced Media Publishing