The first reader to weigh in on a recent post about new fall-prevention guidelines was “h” from Chicago, who wrote: “I also wonder about bifocals causing falls. This is why I’m sticking to two pairs of glasses for now.”

That’s good advice, it turns out.

In a study published last year in the medical journal BMJ, Australian researchers found a decrease in the number of falls among people who switched to single-vision eyeglasses for outdoor activities and stairs.

The results, said the researchers, “demonstrated how multifocal glasses can impair visual abilities needed for detecting obstacles and judging depth.”

So I went back to the complete list of fall-prevention guidelines issued by the American Geriatrics Society and its British counterpart, the ones that focus primarily on incorporating tai chi and medication reduction. There, toward the end of a list of additional recommendations — No. 28 to be exact — was this: “An older person should be advised not to wear multifocal lenses while walking, particularly on stairs.”

Before you schedule an appointment at the ophthalmologist’s, though, or run to out buy an eyeglass lanyard for a parent, bear in mind one caveat from the Australian study: Some participants fell in the process of switching glasses.

Which brings us back to “h” from Chicago, or any other reader who figured this out without reading a study. Any other tips on how to handle eyeglasses without risking a fall?