Common Sense: What is SunGlasses?

How exactly is the core function of sunglasses implemented?​

The core functions of sunglasses are mainly achieved through their special lens design and materials. First, the lens uses materials that can effectively block ultraviolet rays, such as resin lenses or glass lenses with ultraviolet absorbers added. These ultraviolet absorbers can absorb ultraviolet rays in sunlight (mainly UVA and UVB), preventing ultraviolet rays from entering the human eye directly, thereby protecting tissues such as the cornea, lens and retina of the eye, and avoiding the damage to the eyes of ultraviolet rays, such as causing eye diseases such as keratitis, cataracts, and retinopathy. Secondly, the lenses of sunglasses also have the effect of reducing strong light stimulation, which is achieved by using polarized lenses or dyed lenses. Polarized lenses can filter out polarized light reflected by sunlight on smooth surfaces such as water, road surface, snow, etc., reduce the stimulation of strong light to the eyes, and make the field of view clearer and more comfortable. They are especially suitable for outdoor activities such as driving, fishing, and skiing. The dyed lenses evenly absorb or reflect some visible light by adding pigments to the lens material, reducing the intensity of light, avoiding strong light directly from the eyes, and alleviating eye fatigue.​

What are the types of lens materials for sunglasses and what are their characteristics?​

The lens materials of sunglasses are mainly made of glass lenses, resin lenses, PC (polycarbonate) lenses, etc. They each have different characteristics. Glass lenses have high light transmittance and clarity, can truly restore the color of objects, have good visual effects, and at the same time, their surface hardness is high, wear resistance is strong, not easy to be scratched, and have a long service life. However, glass lenses also have obvious disadvantages, namely, they are large in weight, which may bring a certain sense of pressure to the bridge of the nose and ears when worn. They also have poor impact resistance and are prone to breaking when impacted by external forces, which poses safety hazards. Resin lenses are one of the most widely used sunglasses lens materials on the market. They are lightweight and comfortable to wear and will not put too much burden on the face. At the same time, resin lenses have good impact resistance, are not easy to break, have high safety, and can also undergo a variety of special treatments, such as coating, dyeing, polarization, etc., to meet different usage needs. However, the surface hardness of resin lenses is relatively low and easy to be scratched, so you need to pay attention to daily maintenance. PC lenses have extremely high impact resistance and are the best impact resistance among all lens materials. They are not easy to break even when subjected to strong impact. They are very safe, so they are often used in sports sunglasses. In addition, PC lenses are also lightweight, comfortable to wear, and have good weather resistance, which can maintain stable performance under different temperatures and ambient conditions. However, the transmittance and clarity of PC lenses are slightly inferior to glass lenses and some high-quality resin lenses, and are relatively expensive.​

How to choose the right sunglasses according to different usage scenarios?​

It is crucial to choose the right sunglasses according to different usage scenarios, so as to better play the protective role and usage effect of sunglasses. In daily commuting scenarios, mainly to block the ultraviolet rays in the sun and reduce the stimulation of strong light to the eyes, just choose sunglasses with UV400 protection function (can block UVA and UVB 100%) and medium light transmittance. The lens color can be gray, brown, etc. These colors of lenses can better restore the color of the object and will not have too much impact on visual judgment. If you drive frequently, it is recommended to choose polarized sunglasses, because polarized lenses can effectively filter out strong light and glare reflected from road surfaces, water surfaces, improve the clarity of driving vision, reduce driving risks caused by strong light interference, and ensure driving safety. When performing outdoor sports, such as skiing, mountaineering, fishing, golf, etc., you need to choose special sunglasses based on the specific sports characteristics. For example, when skiing, due to the high reflectivity of the snow to sunlight and the high UV intensity, sunglasses with high UV protection performance, high light transmittance (which can also ensure a good field of view under low light conditions) and darker lens colors. It is best to choose frames with windproof and anti-fog functions; when fishing, polarized sunglasses need to be selected to eliminate the strong light reflected from the water surface and clearly see the fish underwater; golf exercises have certain requirements for the color of the lens, and usually choose brown or amber lenses. Lens of this color can enhance the contrast between the lawn and the ball, making it easier to observe the flying trajectory and landing point of the ball.​

What key indicators and details should be paid attention to when choosing sunglasses?​

When choosing sunglasses, you need to pay attention to multiple key indicators and details to ensure that you choose a product that is of quality and suitable for you. First of all, ultraviolet protection capability is one of the most important indicators. Be sure to choose sunglasses with clear UV protection marks, such as the UV400 mark, to ensure that they can block UVA (wavelength 320-400nm) and UVB (wavelength 280-320nm) ultraviolet rays 100%, and avoid buying products without any UV protection marks or non-protective effects to avoid causing damage to the eyes. Secondly, the optical performance of the lens cannot be ignored. High-quality sunglasses lenses should have good light transmittance and clarity, and there are no obvious defects such as optical distortion, bubbles, scratches, etc. The optical performance of the lens can be judged by observing whether the lens surface is smooth and flat, and whether there is deformation or blur when observing the object through the lens. The material and comfort of the frame are also important details that need to be considered when choosing sunglasses. Common materials of frames include metal, plastic, TR90, etc. The metal frame has good texture and high strength, but is relatively heavy in weight; the plastic frame is light in weight and rich in color, but the strength may be slightly worse; the TR90 frame has the advantages of light weight, good elasticity, impact resistance, high temperature resistance, etc., and is comfortable and durable to wear. When making a choice, you should choose a frame with the right size, light weight and comfortable wearing according to your facial contour and wearing habits to ensure that the frame can be stably fixed to the face without being too tight or too loose. In addition, the color of the lens also needs to be selected according to personal needs and usage scenarios. Lens of different colors have different characteristics and scope of application. For example, gray lenses are neutral and do not change the color of the scene; brown lenses can enhance contrast; blue lenses are suitable for use in strong light environments such as snow or beaches, but may change the color of the object, affecting visual judgment, and need to be carefully selected.