What kind of damage can a mascara brush do?

We put Brooke's question to Roger Buckley...

Roger - Well, a mascara brush can be harmful in two different ways. First a slip with the brush when the mascara is being applied can cause a scratch on the surface of the eye - either the white of the eye or the cornea. And whereas that will normally heal very quickly, within 24 hours, it could become infected and then that would become an emergency and require urgent treatment.

The other way in which mascara may be harmful, or the brush may be harmful is that it may actually be infected. When you apply it first to the skin, bacteria will adhere to it and when it's then put back into the container, they will not only survive but they will grow. This was established about forty years ago by some American workers. So, in effect, every time you apply that mascara brush to your lashes, you are reinfecting yourself with your own bacteria.

Chris - But if they're your own bacteria already, is that bad?

Roger - Yes, but they have increased in number in the meantime in the container, so you're putting on a larger concentration of bacteria. And there's an association with the use of mascara with infections of the eyelids. Blepharitis, styes and so on are commoner in people who use mascara.

Kerstin - Is it worse if I share my mascara with my best friend then?

Roger - Well, you don't know where your best friends been, do you? You wouldn't share contact lenses and, for the same reason, you wouldn't share mascara brushes I suggest. It's just not healthy.