Can a worn or damaged lens coating be professionally reapplied?

Usually, no—not as a normal repair. Recoating a lens element generally requires removing the old coating first, and that process can involve polishing or other work that risks altering the lens surface. Because lens curvature and surface accuracy are very precise, that can make recoating impractical.

Historically, some makers did offer recoating services, especially for older lenses, but that depended on factory equipment and exact matching of the original optical surfaces. That kind of service is uncommon today.

In practice, if coating damage is severe enough to matter, replacing the affected element—often the front element—is usually more realistic than stripping and recoating the original one. For many lenses, especially lower-value models, even element replacement may not be economical compared with replacing the lens.

Also, minor coating wear often has little visible effect on image quality, so repair may not be necessary unless you’re seeing clear flare, contrast loss, or other image problems.