Sunglasses: how to really choose them

Sunglasses are often thought of as a style accessory, but their function is first and foremost medical: to protect the eyes from ultraviolet radiation, the invisible portion of sunlight capable, over time, of damaging the structures of the eye. Just as we protect our skin with sunscreen, we should protect our eyes with a good filter and choosing well makes a real difference.

Indeed, chronic exposure to UV rays has been implicated in several conditions: from cataracts, the early clouding of the lens, to certain diseases of the ocular surface such as pterygium (an abnormal growth of tissue on the cornea, typical of those who spend a great deal of time outdoors), to a possible contributing role in macular degeneration. Protection, then, is not a refinement: it is genuine prevention.

Polarized lenses reduce glare from surfaces such as water, snow, and asphalt.

What really matters: the UV filter

The most important, and least intuitive, point is this: a dark lens color does not equal protection. A dark lens without a UV filter is actually more dangerous than no sunglasses at all, because by reducing light it causes the pupil to dilate, letting more ultraviolet rays into the eye. This is why you should always check that the glasses carry the label “UV400” or “100% UV,” which guarantees protection against the entire harmful spectrum. Be wary, therefore, of bargain sunglasses from street stalls with no certification at all.

Category, color, and material

Sunglass lenses are classified into five filter categories, from 0 (clear lens) to 4 (very dark). For everyday use in the city, category 2 or 3 is perfectly fine, while category 4, very dark, is reserved for high-altitude mountains and is not permitted while driving. Lens color is mainly a matter of comfort: gray preserves natural color rendering, while brown increases contrast. Polarized lenses, finally, reduce glare from surfaces such as asphalt, water, and snow, and are particularly valued for driving and outdoor sports.

Chronic sun exposure leaves its mark on the eye’s tissues: UV protection is prevention.

Not just a summer accessory

It would be a mistake to think of sunglasses as a beach item only. Ultraviolet radiation is present all year round, and in certain winter conditions it can be even more intense: snow, in particular, reflects a large portion of UV rays and can cause so-called “snow blindness,” a painful inflammation of the cornea. Protection should also be increased at the seaside and on boats, where water reflects light, and in the mountains, where the atmosphere filters less.

The right shape, and children

It’s best to choose wraparound frames, which also protect from the sides and prevent rays from entering around the edges. Children deserve particular attention: their eyes are more delicate, and their lens, still highly transparent, filters out less UV than an adult’s, letting more radiation reach the retina. For them, glasses with a certified filter are not an indulgence, but a healthy habit worth building from an early age.

In conclusion

Choosing sunglasses, in the end, means reading the frame’s label before anything else: UV protection comes before fashion and before price. Let’s enjoy the sun, days outdoors, and the warm season in all its forms, while always remembering to protect our eyes when we’re outside, a simple habit today that pays off, in health, for a lifetime