As a very delicate part of the human body, the eyes are easily sunburned by ultraviolet rays. Because different structures of eye tissue absorb ultraviolet rays of different wavelengths, it can lead to many acute and chronic ophthalmic diseases and injuries, such as pannus pterygium, solar keratitis and senile macular degeneration. Therefore, in the summer with sufficient sunshine, eye sunscreen is particularly important.
Wearing sunglasses outdoors in summer has a certain protective effect on the eyes, but when choosing sunglasses, we should pay attention to that good sunglasses can filter out more than 96% of the ultraviolet rays in the sun. Poor Sunglasses not only have no anti ultraviolet function, but also expand the pupils for a long time, increase the light entering the eyes and increase the eye damage. In particular, sunglasses are not suitable for everyone. Sunglasses are easy to cause pupil dilation, so glaucoma patients should use them with caution; Patients with myopia and astigmatism may have spherical aberration due to pupil enlargement, which will affect the imaging quality.
At present, there are many Sunglasses with ultraviolet absorption on the market, which can be purchased according to individual needs. Lenses mixed with metal element oxides, in which the metal element oxides can absorb 95% ultraviolet and infrared rays; The surface of the reflective lens coated with a reflective film is coated with a layer of vacuum metal film, which can not only pass through visible light, but also reflect harmful ultraviolet radiation; Polarizer has the function of polarizing light, so it can block all harmful light without affecting the transmission of visible light. After natural light is filtered by polarizing lens, it can only let light in one direction pass through, so as to effectively protect eyes.
In addition, sunglasses are not only needed in summer. Many people mistakenly think that the sun is not strong on cloudy days and the weather is not hot, so they take it lightly and unknowingly irradiate more harmful ultraviolet rays. In fact, sunglasses need to be used all year round, not only on sunny days, but also on cloudy days. Even on cloudy days with thin clouds, you must still refer to the UV index forecast and do a good job in sunscreen.