How To Choose The Right Sunglasses
The German Association of Ophthalmologists said that the right sunglasses should provide effective protection for the eyes from harmful ultraviolet rays.
The association explained that the degree of darkness of sunglasses lenses is divided into categories ranging from 0 to 4, noting that at the lowest category the lenses absorb 20% of the light; So it’s suitable for cloudy days and evenings, while Category 1 filters 20% to 57% of light and can be used during choppy weather.
Class 2 filters absorb 57% to 82% light, while a Class 3 filter absorbs 82% to 92%, making it suitable for bright water surfaces, beaches and mountainous areas. For mountain heights, category 4 is required.
The Right Sunglasses Should Have Mark (UV400)
The association added that the wavelength of harmful sunlight may reach 400 nanometers, which requires wearing glasses that include the (UV400) mark, which means blocking all radiation, whose wavelength reaches 400 nanometers.
The association indicated that the color of the lenses of the glasses may cause a change in colors in the surrounding environment, explaining that brown, gray and green lenses are the least lenses that change colors. Yellow or orange lenses increase color contrast and have a relatively low dazzling protection.
The orange lenses are suitable for outdoor sports; It enhances the contrast of green, but results in striking colors not being perceived as correctly as those of traffic lights.
The association also stressed the need for the glasses to be large enough to cover the eyebrows, in order to protect the eyes from ultraviolet rays and dazzle from the sides as well.
It is also important that the sunglasses are of a suitable size, so that the nose pads or the arms do not press on the face. It is also better if the nose pads are made of soft plastic material, in order to flexibly adapt to the shape of the nose.
The association stressed the importance of sunglasses for children in particular; Because their pupils are larger than that of adults, and the lenses of their eyes transmit more light as well. So they inevitably need sunglasses that offer 100% UV protection on sunny summer days.