A reader writes:

In 1996 I was injured in a bicycling accident.  Because my helmet was not secured correctly, I suffered a skull fracture transverse to the cochlea of my left ear.  There is no treatment--not surgery, not a hearing aid--that can restore the hearing in that ear.  As a teacher, my work in the classroom has changed radically; for the first two years I thought I might have to change careers.  I have learned to compensate (for instance, the loud kids now go on my left, since I can still hear them, and students who want my attention need to give a visual signal, since stereolocation requires two functioning ears).

My doctor said (and I believe) that I am fortunate.  People in similar accidents have suffered brain damage that altered their lives more significantly than mine has been altered.

Wear the helmet, and fasten the damn chin strap correctly.