Ultraviolet rays aren’t the only way the summer sun can injure your eyes. Some researchers found that when contact-lens solution is stored for several weeks at 60°C—equivalent to the inside of a parked car on a hot day—it loses its ability to kill the microbes that may be lurking on your lenses or in your storage case. As a result, you risk infecting your eyes with bacteria and fungi. Research shows that temps as low as 30°C can be hot enough to decrease the disinfecting power of lens solution, so always stow the stuff in an air-conditioned room.