The eye is a symbol of omniscience.  It is the all-seeing God.  It is also a symbol of virtually all solar or sun gods (the spiritual sun is often thought of as the eye of God).  It is also a symbol of intuition and spiritual visions.  It is a symbol of mystics representing Light or enlightenment and spiritual knowledge (gnosis).  The eye often found near the top of a temple, cathedral or lodge represents a solar door that gives access to higher realms.  An eye inside of a triangle represents the all-seeing eye of an omnipresent and omniscient God.  In Buddhism, the third eye of Buddha, the "flaming pearl" represents spiritual consciousness and wisdom.  In China and Japan, the left eye represents the sun and the right represents the moon.  In the Occident, it is just the opposite.  In the Book of Revelation, the seven eyes are considered to represent the seven spirits of God.  In Oceania, the sun is the "Great eye-ball".  In Masonic symbology, the eye is usually depicted with rays of light coming from it like rays coming from the sun.  The eye can also symbolize focus, clarity, perception, prophecy, vision and awareness.  In the Tarot, an eye is said to represent the third eye, the pineal gland, which gives spiritual vision.
    In dreams, to see open eyes means one is awakening spiritually, but closed eyes means you are still spiritually asleep.