I'm intrigued with this idiom in the Scriptures. I always check Bible study tools online for the various translations from different versions, pay attention to the context, check my trusty dictionary and google for other interesting info.
The three main locations for this phrase are Zechariah 2:8 “...he who touches you touches the apple of His eye.” Deuteronomy 32:10 “He found him in a desert land, and in the howling waste of a wilderness; He encircled him, He cared for him, He guarded him as the [apple] pupil of His eye.” And in Psalm 17:8 as a prayer of David or protection against oppressors. “Keep me as the apple of the eye.”
It's exciting to mine all of the gold out of those few passages! Other translations of the term are: “Keep, guard, watch me with your very pupil; keep your eye on me; protect me like the pupil of your eye; as you would your very eyes; take good care of me, just as you would take care of your own eyes.”
It's important to understand that the term is an anthropomorphism. Of course God doesn't literally have “an eye.” According to the Bible Dictionary, “Scripture affirms that God is spirit rather than flesh, and more unlike mortals than like them. But to make the mystery of God more accessible to human minds, the Old Testament also uses language that gives God the emotions and actions of a mortal being: anger, sorrow, love, etc. Sometimes God is given physical characteristics: a face, hand, arms, eyes, ears, etc. Such anthropomorphic language reminded Israel that God is “personal,” capable of entering into a deep and genuine relationship with human persons. God was not a remote, emotionless power, but rather a being whose love for His Chosen people was expressed in actions they could see and remember.”
In these Scripture contexts it is clear that the “He” refers to God Himself, and His eye is meant in an anthropomorphic sense. And the “him” who is the object of His affection and protection and desire is first of all His Chosen people of Israel, but also more personally us—you and me. Wow! When Jesus came to earth as the Son of God, He became flesh and expressed that personal, intimate love for us in a tangible way.
The phrase apple of my eye refers to something or someone that is cherished above all others. Its meaning does indeed derive from an expression signifying the pupil of the eye, one of the most sensitive and precious parts of the body. We all know what an instant reflex action we have when something is thrown at or comes toward our eye—we instinctively throw our hands or arms over our face to protect us against the object. Since our sense of sight is incredibly precious to us and in need of protection, calling someone the apple of my eye came to mean that the person was cherished and loved and treasured. In fact, we would do almost anything for them because they are the object of our affection. We somewhat tolerate an eyelash on the white of our eye, while making every effort to get rid of it. But let it barely touch the pupil, [the apple] and everything else is of secondary importance.
So we may understand in this visual idiom how precious each one of us is to God. What an honor for you and me to be the objects of His love! “We love Him because He first loved us.” He lavishes His love upon us. As for me, I'm happy to be His "little doll" “reflected in His eye” as He watches over me, guards me, and protects me with great tenderness. No one can touch me unless they touch the apple of His eye first. There is no obscure place I could go where He doesn't see me. (Psalm 139:7-12) Even when I wander around “in my desert land and in the howling waste of the wilderness of my own making, He encircles me, [hugs me with His arms around me] and cares for me” as He would regard His own eye.
With David let us pray, “Keep me as the apple of Your eye!”