Sunglasses, which prevent the negative impact of ultraviolet radiation (UV) on the eyes, are divided into several categories. “Quality sunglasses should be marked as UV 400, which means that they absorb sunlight with a wavelength of up to 400 nanometers. The second important parameter is light transmission, respectively tinting of glasses, which is divided into categories 0 to 4,” explained for TASR the head of the eye clinic of St. Cyril and Methodius in Bratislava Petr Kolář with the fact that not every category is also allowed for driving.
He explained that category 0 and 1 are “fashionable glasses” with minimal tinting and protection against sunlight. They are suitable as protective glasses against wind and dust. In category 2 are glasses with protection of 57-81 percent and they belong to sunglasses with a medium dark filter for everyday wear and drivingadded the expert.
Category 3 includes sunglasses suitable for staying by the sea or in the mountains. “Category 4 includes sunglasses with very intense coloring, suitable for ski mountaineering and staying in high mountains and on glaciers. Category 4 sunglasses are not allowed to be worn while driving,” explained Kolář.
In addition to the mentioned two parameters, according to him, it is possible to use sunglasses incorporate polarized lenses that reduce glare on various surfacessuch as water or glass, so they are suitable for driving.
Kolář pointed out that UV radiation in adequate amounts is beneficial for the production of vitamin D, but excessive exposure to the human body results in a number of negative changes. “Of the most serious skin tumors – malignant melanoma, which can also arise on the retina, or basal cell carcinoma, which in case of late surgical intervention can have destructive consequences both for the eye and for other parts of the body. In addition to tumors, however, it can cause inflammation of the conjunctiva, cornea, cataracts, damage to the retina – the so-called solar retinopathy or macular degeneration. People with light-colored eyes, whose iris has less pigment that captures this radiation, are more at risk,” stated.
He reminded that it is also necessary to protect the eyes in the summer from wind and dust, which can cause unpleasant irritation of the conjunctiva, or the introduction of a foreign body into the conjunctival sac. It must then be rinsed with clean water or artificial tears. “Unpleasantness in terms of eye discomfort can also be caused by excessive use of air conditioning. In air-conditioned spaces, it is advisable to use artificial tears without preservatives more often,” concluded.
