What term refers to an eye that has a lighter, almost white appearance?

The term that describes an eye with a lighter, almost white appearance is known as a "wall-eye." This term is often used in equine terminology to refer specifically to horses that have a bluish or glassy-looking eye, which can result from a lack of pigmentation in the iris. This condition may give the eye a more pronounced or "wall-like" appearance, distinguishing it from other types of eye colorations in horses.

The other terms do not accurately capture this specific feature. For instance, "moon-eye" typically refers to round, full eyes but does not denote the light coloration. "Sun-eye" is not a widely recognized term in equine contexts, and "dark-eye" clearly contradicts the description of a lighter appearance. Thus, "wall-eye" is the most appropriate and specific term for an eye exhibiting the described characteristics.