In Revelation 3 below, Jesus is talking to the church in the end times. He tells them what is wrong, and says that they are blind, and then at the end tells them that they should anoint their eyes with eye salve, that they may see. All of this is spiritual language. They are not physically blind, but they have no spiritual discernment, therefore they can’t know that they are spiritually wretched, miserable, naked, etc. When you have no spiritual discernment, you cannot know your own condition, or that the devil is deceiving you. 

Matthew 6:23   “But if your eye is bad, your whole body will be full of darkness. If therefore the light that is in you is darkness, how great is that darkness!”

Revelation 3   ¹⁷ “Because you say, ‘I am rich, have become wealthy, and have need of nothing’—and do not know that you are wretched, miserable, poor, blind, and naked— ¹⁸ I counsel you to buy from Me gold refined in the fire, that you may be rich; and white garments, that you may be clothed, that the shame of your nakedness may not be revealed; and anoint your eyes with eye salve, that you may see.”

Jesus told His disciples that when the Holy Spirit came into their lives, He (the Holy Spirit) would lead them into all truth. He would point our their sins, and show them their condition, so that they would know what they needed from God. In the Revelation passage, the church does not have the Holy Spirit, who would enlighten them and show them truth. 

John 16     ⁷ “Nevertheless I tell you the truth. It is to your advantage that I go away; for if I do not go away, the Helper will not come to you; but if I depart, I will send Him to you. ⁸ And when He has come, He will convict the world of sin, and of righteousness, and of judgment: ⁹ of sin, because they do not believe in Me; ¹⁰ of righteousness, because I go to My Father and you see Me no more; ¹¹ of judgment, because the ruler of this world is judged.

¹² I still have many things to say to you, but you cannot bear them now.¹³ However, when He, the Spirit of truth, has come, He will guide you into all truth …”

Revelation 5:6   And I looked, and behold, in the midst of the throne and of the four living creatures, and in the midst of the elders, stood a Lamb as though it had been slain, having seven horns and seven eyes, which are the seven Spirits of God (the Holy Spirit) sent out into all the earth.

In the passage above, the Holy Spirit is spoken of as “the seven Spirits of God” and is shown as “seven eyes”, showing that the spiritual discernment (which is lacking in the last days’ church) is given by the Holy Spirit.

I hope I didn’t confuse you. The Holy Spirit is the One who enables us to know spiritual things, to avoid deception, and show us all truth. He is therefore our Giver of spiritual discernment, the eye that Jesus spoke about. God bless!