As previously mentioned, being on or near snow or ice increases UV exposure, and high altitude winter activities increase UV strength. When combined, reflective surfaces, and high altitudes, double your risk of getting sunburned eyes, or a temporary loss of vision, known as snow blindness.
In addition to preventing snow blindness, wearing sunglasses (especially polarized) from November through March can help reduce winter glare and vision-related headaches.
Thank you to Claudine! (wearing Maui Jim)