The eyes are often said to be the windows of the soul, which means when a character is described in a book, the eyes will be a significant predictor of the person's personality - or of the scene itself.
On a driver's license, eye colors are divided into four categories: brown, hazel, blue and green. But in reality, brown eyes can be mahogany, chestnut, amber, honey, russet, chocolate, or even tan.
Hazel eyes have flecks of green and gold. They can appear to change colors, based on the character's surroundings, and appear more blue or green or brown... These eyes also change colors depending on emotion, especially depicting passion or fear...
Green eyes can be emerald or peridot, olive or bottle green... Sea green or jade...
Blue eyes can be periwinkle or cobalt, sapphire or cerulean, indigo or even purple. Both green eyes and blue can be deep or pale.
Eyes and eyebrows can depict emotion: narrowed in suspicion, furrowed or flashing in anger, widened in fear or apprehension. They can blink rapidly, wander endlessly, or stare unblinking.
Eyebrows can be heavy or thin, pale or dark, drawing the eye upward or seeming not to appear at all.
Lines around the eyes can depict laughter and a good nature or evil or worry.
Lashes can be pale or dark, thick or thin, silky or coarse.