Before Yaakov went down to Egypt, Hashem appeared to him in a prophetic dream with a consoling message: "Do not fear going down to Egypt, for there I will make you a great nation. I will go down with you to Egypt, and I will certainly bring you up, and Yosef will put his hand on your eyes" (Bereishit 46: 2-4).
Many commentators struggle with the implication of the phrase, "Yosef will put his hand on your eyes." The Rashbam understands that Yosef would take care of all of Yaakov’s needs. Ibn Ezra goes in the direction that Yosef would stay with him until Yaakov’s death, at which time he would cover Yaakov’s eyes, as is customary. According to the latter commentary, it is connected to the matter of leaving Egypt, which also occurred only after death. According to both explanations, the order of the sentence’s components is problematic, as the matter of Yosef’s hands took place before Yaakov left Egypt.
We find a totally different approach to this concept in Rav Meir Simcha’s work, Meshech Chochma. The covering of the eyes was an assurance that Yaakov need not and should not concern himself with a theological investigation as to the reason that he had to go down to Egypt. The reason, he was told, was similar to the fact that Yosef had to suffer in a manner that was hard to understand at the time in order that he would make it to Egypt, be a ruler, and publicize correct theologies.
According to the Meshech Chochma, the migration to and from Egypt that accompanied the separation from Yosef was something that had a very special purpose that was hidden for quite some time. With Yosef’s help and with that of the subsequent migration of his brothers and their families, a major step was taken in the effort to "fix the world in the dominion of Hashem." Yosef, viceroy to Pharaoh, tried to create a monotheistic revolution in the idolatrous Egypt and publicize correct theologies. If the matter of Yosef’s mission had only been known earlier, then a lot of wonders would have been clarified.
The p’sukim in Tehillim (105: 17-22) actually corroborate this thesis very strongly. "He sent before them [Egypt] a man; Yosef was sold as a slave. They oppressed his leg with shackles; iron went to his soul. Until the time that His word came, the word of Hashem strengthened him. He sent a king and untied him; the ruler of nations opened his shackles. He made him a master in his house and one with dominion over all of his possessions. To incarcerate his officers at will, and his elders he would make wise." Yosef’s mission was to bring an improvement in the spiritual approach through his impact on the elite of the superpower’s leadership.
It is important to remember these days, when we think the whole world is against us, that the final goal is to unite humanity around the idea of belief in One G-d, with the center of this theological movement being in Jerusalem, the eternal capital of the Jewish people.