We don’t hate winter (see: bundling, ice skating anywhere), but that doesn’t stop us from all-out crying after two minutes in the cold. Deep-seated emotional pain? Nope—it’s our eyes’ normal biological response.
The Need-to-Know 
Your eyes need to stay lubricated to see, which doesn’t go well with cold, dry winter air, says James Auran, M.D., chief of ophthalmology at New York’s Harlem Hospital Center. The wind and lack of moisture leads your eyes to tear up, trying to keep themselves at max visibility and minimum discomfort. It’s basically a reflex response—and when the tears overwhelm your tear ducts, they make a dramatic exit down your cheeks (and nose, so no worries about wiping it on a sleeve).
The lack of humidity makes your eyes tear more, as does brightness: All that light reflecting off snow makes your eyes more sensitive. Recent research has found that your eyelash length also plays a role in how much you tear up. Lashes at one-third your eye’s width best keep tears from evaporating (meaning less reflexive waterworks), with any longer funneling air in and creating more irritation, and any shorter allowing greater evaporation of tears—triggering a flood of them to keep you seeing.1
Your Action Plan
Glasses are …