lose sight of
Overlook, fail to take into account, as in We must not lose sight of our main objective, or Beverly never lost sight of her humble beginnings. This metaphoric expression alludes to physical sight. [Early 1700s] For an antonym, see bear in mind.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.