The eye here speaks of the outlook of the heart. A single eye means one that is fixed on the spiritual.“Evil” suggests a sinful outlook, a double vision.
Matthew 6:34 – KJV- … Take therefore no thought for the morrow:…
Thought: merimnaō , mer-im-nah’-o= stems from the verb merizo (divide) and nous (mind). Worry cleavers the mind, splitting thoughts between today and tomorrow. It means: to be troubled; to be anxious; to be fretful; or to be worried about something.