Can clear lenses protect us from UV rays? Nowadays, there is widespread awareness of the dangers of direct exposure of our eyes to sunlight. This is why we often hear about glasses with UV protection in their lenses. UV and Blue light protection Nowadays, there is widespread awareness of the dangers of direct exposure of our eyes to sunlight. This is why we often hear about glasses with UV protection in their lenses. When we are exposed to sunlight for extended periods of time, we risk damage to the eyes in the form of disorders such as cataracts, macular degeneration, pinguecula, keratoconjunctivitis and photokeratitis, which, in the most severe cases, can lead to temporary loss of vision. By definition, sunglasses are designed to protect us from harmful solar radiation, but it must be said that not all types of sunglasses are fitted with lenses that block 100% of UV radiation. Protective sunglasses are recognizable by a “UV400” specification, which indicates that the lenses block ultraviolet rays in frequencies up to 400 nanometers, which include both UVA and UVB rays. What not everyone knows is that UV protection is in no way related to the color of the lenses. In fact, you will find dark lenses that don’t provide 100% protection from UV rays and completely transparent lenses that totally protect up to 400 nanometers. So how does it work? Before getting into the differences between one lens and another, we need to start from an analysis of the solar spectrum. Light is that part of the electromagnetic spectrum that is visible to the human eye. It is an electromagnetic wave emitted by the sun and filtered by the atmosphere before reaching the ground. It encompasses wavelengths, i.e. the distance between the peaks in a series of waves, from 400 nm to 700 nm. Ultraviolet (UV) radiation is in the invisible portion of the electromagnetic spectrum, from 100 to 400 nm, and may be divided into three bands (i.e. UVA, UVB and UVC) based on their biological effects. Until a few decades ago, we used to worry mainly about UVA rays, which are the ones related to tanning. With wavelengths between 280 nm and 400 nm, UVA rays completely penetrate the ozone layer in the upper part of the atmosphere, pass through it, and reach the earth’s surface. Conversely, the ozone, together with the water vapor, oxygen and carbon dioxide present in the atmosphere, block about 90% of incoming UVB rays (280-315 nm) and all of the incoming UVC rays (100-280 nm). Today, however, due to pollution related to greenhouse gases, this protective layer is increasingly thinning, so the danger from UVB rays is growing. Both UV-A and UV-B radiation can have short and long-term negative effects on our eyes and vision, but UV-B rays, the high energy of which is capable of impacting the retina, are particularly dangerous for our eyes. In addition to ultraviolet rays, which have wavelengths below 390 nm, danger to our eyes also comes from high-energy visible (or “HEV”) light. Known colloquially as “blue light”, HEV light is a blue-violet light with wavelengths between 400 nm and 500 nm, which, unlike the UV bands, is included within the visible spectrum. The shorter wavelength HEV light falls within the blue-violet portion of the spectrum. This is light emitted both by the sun and by artificial light sources. Light from the LED screens of computers, phones, tablets and televisions is one example. Prolonged, unprotected exposure to HEV light can cause damage to the eyes, especially to the retina, and is a risk factor for the onset of age-related macular degeneration. Sunglasses and corrective glasses: which lenses offer the right protection? SUNGLASSES: To best protect our eyes, we must never forget to wear sunglasses and should always have our children wear them before going outside. When marked with the appropriate “UV” label, sunglasses protect against ultraviolet rays up to 400 nanometers. And what about blue light? As mentioned above, blue light also comes from the sun and is actually up to 30 times greater than the blue light emitted by electronic devices. This is why many colored lenses now include blue-light protection (or “blue block”), and they are becoming more and more popular. PRESCRIPTION GLASSES: The lenses most in demand are, without doubt, those with blue-light filters (such as our Blue Natural lenses), given the widespread use of digital devices and remote work. Lenses with HEV filters protect up to 420 nanometers, so they completely block all UV rays. As a result, when you are wearing blue-block glasses, you are 100% protected against HEV light. If you feel you don’t need to protect against blue light, there are also transparent lenses with UV protection of up to 400 nanometers, such as our NoUV lenses. Finally, it should be noted that UV and blue-light protection are available both in the lenses themselves and as a lens coating. What does this mean? In the first case, the material responsible for absorbing harmful rays is mixed directly into the raw material of the lens, as in the case of our NoUV or Blue Natural lenses. In the second case, the protection is applied later as a lens coating. There are specific coatings, such as our Chroma for blue light or Performance NoUV for UV rays, that can be applied to the surface of the lens. Of course, the most durable solution is a lens made of a protective material, given that coatings are more subject to scratches and other wear and tear over time. Nonetheless, high-quality coatings are an excellent solution, especially since the first type of protective lenses are not available in all indices. When choosing lenses and frames, it’s best to opt for a frame design that follows the shape of your face as closely as possible. In this way, you limit the amount of sunlight that reaches your eyes from the sides and from above.