Semantics

Под левым глазом у него был синяк, а правый настолько распух, что вовсе не открывался. There was a bruise under his left eye, and his right one was so swollen that he couldn't open it at all.
Вечерняя работа над чертежами отразилась на его глазах. Nighttime work on the drawings affected his eyes.
This entry is primarily concerned with the use of the word глаза denoting the human eyes both as part of the face and as the organ of sight. This term can be used to refer to animals as well. No specific words or expressions exist referring to eyes of animals; common sense will dictate which expressions can or cannot be used to refer to animals.

The plural form глаза is also used to mean "sight, vision, ability to see," e.g. Работал всю жизнь в темноте, вот и лишился глаз. "All his life he worked in poor light, and finally lost his eyesight." This meaning is also described in this entry.

The following meanings are not described in this dictionary: "an unusual perceptiveness for certain things" (материнский глаз "a mother's eye," хозяйский глаз "a proprietary eye") and "care, supervision, looking after" (Ребёнку нужен глаз "Someone has to keep an eye on the child").