Or HaChaim on Deuteronomy 34:1/אור החיים על דברים ל״ד:א׳

1ויראהו ה׳ את כל הארץ; G'd showed him the entire country. The Torah may mean that G'd enhanced Moses' natural eyesight so as to enable him to see the whole land in all its details. This could be achieved by one of two means. 1) To provide Moses with additional eyesight by enabling him to utilise the original light G'd created on the first day of creation which He withdrew from man as a result of Adam's sin. According to Chagigah 2, Adam had been able to see from one end of the earth to the other by means of that light. 2) Or, G'd brought the land closer to Moses so that he could see it in detail with his normal eyesight.