Every time your skin is exposed to daylight, it incurs photodamage. 'Photodamage' is a scientific term used to describe the ageing effect of light—specifically, sunlight—on all skin types. Photodamage causes loss of collagen, degradation of elastin, malfunction of pigment cells, dryness, and dehydration.
The visible effects of photodamage are inelasticity, wrinkles, sagging, uneven skin tone, and age spots. These are normal signs of ageing; however, photodamage accelerates their formation exponentially. Our skin is exposed to many types of light daily, but the type most responsible for photodamage is UVA. Unlike UVB light, which changes in intensity seasonally, UVA remains consistent all year round. UVA light causes photodamage without sunburn and without heat.
An estimated 80% of external ageing factors are attributable to sun damage. If you're serious about anti-ageing skincare, eye cream with SPF is as necessary in winter as it is in summer.