In the deuterocanonical Trek Litverse (specifically the eBook *The Insolence of Office*), in addition to what Andrew mentioned in his answer, it was because of security concerns as described [here][1]. To summarize, following the events of *Generations* in which his VISOR was hacked and used to aid in the destruction of the Enterprise-D, and coupled with the previous incident of VISOR-based brainwashing in *The Mind's Eye*, La Forge was ordered by Admiral Hayes (of various screen appearances) to replace his VISOR as a security risk or be reassigned to a less-sensitive post.

  [1]: https://memory-beta.fandom.com/wiki/VISOR