After inserting your contact lenses and rinsing the case with disinfectant, do you let the case air-dry face-up or face-down?

Face-down seems to be better, says a recent study that checked microbial contamination in cases placed in four different locations: toilet, bathroom, office and bedroom. The cases were rinsed with sterile saline and placed on facial tissue paper.

Cases that dried face-up were significantly more contaminated than the face-down cases (71 percent vs. 12 percent). For the face-up cases, the humid environments (toilet and bathroom) produced more contamination than the non-humid environments (office and bedroom). But for the face-down cases, the contamination amounts were similar across environments.

By the way, 33 percent of all the contact lens cases were contaminated with multiple species of bacteria and/or fungi, not just one species.

The study report appeared in the July issue of the journal Optometry and Vision Science.