lose sight of
lose sight of {v. phr.}
1. Not to be able to see any longer.
I lost sight of Mary in the crowd.
I watched the plane go higher and higher until I lost sight of it.
Contrast: CATCH SIGHT OF.
2. To forget; overlook.
Johnny was so interested in the game he lost sight of the time.
No matter how rich and famous he became, he never lost sight of the fact that he had been born in the slums.
Categories:
Source: A Dictionary of American Idioms