Sunglasses are not only practical tools to protect eyes from strong sunlight radiation but are also fashion accessories that showcase personal style and taste. The primary principle of radiation protection from sunglasses is through a special coating on the lens that filters out ultraviolet rays. Common sunglasses lenses have two types of radiation-resistant coatings - one is a coated anti-radiation that uses coating technology to cover a chemical coating on the lens that can absorb, reflect, or transmit ultraviolet rays; another is a dyed anti-radiation that disperses dye in the lens material, allowing the dye to absorb the energy of ultraviolet rays.
1. UV Protection Level of Sunglasses
Some sunglasses are marked with a UV value, which indicates the ability to block ultraviolet rays. Generally, UV380 can effectively block ultraviolet rays, and UV400 can filter out 99%-100% of ultraviolet rays. Of course, if you have higher protection needs, you can choose sunglasses with a "UV100%" mark.
2. Color of Sunglasses
- Gray Sunglasses
Gray lenses are relatively neutral lenses. While weakening the light, they will not greatly change the true color of the object. They can filter almost equal amounts of color in sunlight and filter infrared and 98% of ultraviolet rays. The original color of the scenery will not change due to the lens, and it can also block strong light, making it suitable for outings.
- Brown Sunglasses
Brown sunglasses can completely absorb ultraviolet and infrared rays. The color change is relatively soft, which can make the eyes more comfortable. They are suitable for driving, dusty or smoggy weather.
- Green Sunglasses
Green sunglasses have strong light transmittance for green, which is relatively comfortable and suitable for people with easily fatigued eyes. They can filter infrared light and 99% of ultraviolet rays, but the green lens will change the color of some sceneries. The effect of blocking light is slightly inferior to that of gray lenses, suitable for outdoor wear.
- Blue Sunglasses
Blue sunglasses cause a significant color change in everyday sceneries. It is recommended not to wear deep blue lenses in daily life. However, blue lenses can effectively dissolve the light reflection brought by seawater and the sky, so they are more suitable for wearing in seaside environments.
- Red Sunglasses
Red sunglasses can filter 95% of ultraviolet rays and some shorter-wavelength visible light, but in fact, red lenses are similar to uncolored lenses and do not have better protection than general lenses. They are more suitable for beauty lovers as a fashion accessory.
- Mercury Sunglasses
The surface of the lens is coated with a high-density mirror coating, so it can easily reflect visible light, suitable for people who are active outdoors for a long time.
3. Choose Sunglasses Frame According to Face Shape
When choosing the style of sunglasses, the first thing to consider is your face shape, as different face shapes suit different types of frames.
- Oval Face: Any style is suitable. The frame should not be too thick or too thin, and should not be wider than the face.
- Square Face: Suitable for wearing sunglasses with a curvature. These sunglasses have a narrower top of the frame and gradually widen at the bottom, which can soften the angles of the face and make it appear softer.
- Round Face: Suitable for wearing square or cat-eye sunglasses. These sunglasses have a wider frame, which can highlight the contours of the face and make it appear longer and thinner.
- Long Face: Suitable for round or oval sunglasses. These sunglasses have a wider top of the frame and gradually narrow at the bottom, which can balance the length of the face and make it appear softer.
- Flat Face: Choose darker lenses and frames to highlight facial contours.
4. Sunglasses Lens Materials and Functions
4.1 Sunglasses Lens Materials
Sunglasses lenses come in a variety of materials, including glass, resin, nylon, PC, and TAC, among others.
- Glass Lenses: Characterized by high transparency and scratch resistance, suitable for individuals with strong prescription needs and those requiring protection from intense light. Glass lenses have the best optical performance among all materials, but due to their heavy weight and fragility, their use has gradually declined.
- Resin Lenses: Resin lenses are one of the most widely used lens materials today, offering advantages such as being lightweight, heat-resistant, and having strong impact resistance. When used in sunglasses, the most distinctive feature of resin lenses is their strong coloring performance. With a variety of styles and affordable prices, resin lenses are the ideal choice for most people.
- Nylon Lenses: Nylon lenses are highly flexible and offer professional protective functions, making them the choice for athletes and safety professionals. However, they are more expensive and prone to scratches.
- PC Lenses: PC lenses have very strong impact resistance and are not easily damaged, but their optical performance is quite unstable.
- TAC Lenses: TAC materials are corrosion-resistant and lightweight, but they scratch easily. They are widely used despite their unstable optical performance, and polarized lenses in particular utilize this material.
4.2 Sunglasses Lens Functions
The functions of lenses are mainly achieved through "coating," which involves depositing single/multiple layers of optical film on the lens surface, allowing the lenses to block ultraviolet rays, reduce eye fatigue, and enhance aesthetics. There are roughly three main categories of functional lenses: polarized lenses, protective lenses, and photochromic lenses.
Polarized Lenses
Intense light can cause glare, which is dangerous when driving or participating in outdoor activities as it can significantly impair visibility. Long-term exposure to strong light can lead to eye damage and even conditions such as astigmatism or cataracts.
Polarized sunglasses effectively solve this problem by eliminating scattered light, softening the light, and essentially eliminating the impact of strong light and glare.
Polarized lenses typically have seven layers, each with a different function. Combined, they provide ultraviolet protection, filter harmful rays, combat intense light and glare, and offer scratch and impact resistance.
Protective Lenses
The speed of outdoor sports is often quite fast, and eyes are very fragile. Sunlight, wind, and dust can all pose unexpected dangers, so goggles are commonly worn in outdoor sports. Compared to polarized lenses, protective lenses require more - they need to consider not just the polarizing effect but also the protective effect, ensuring good polarization, high strength, high wrap-around, good stability, and good breathability.
Photochromic Lenses
These lenses can change color based on the intensity of light. Some sports eyewear features this function, allowing users to adapt to a wider range of outdoor environments. Some prescription glasses also offer this feature, which can be a consideration for those who are nearsighted and do not wish to switch glasses frequently.
Additionally, when selecting sunglasses, keep in mind the following points:
- Stability: Choose sunglasses that are stable. If you shake your head or jump and they fall off, they are definitely not the right size.
- Comfort: If the arms of the glasses are too tight, causing headaches, it's not reasonable to keep them – do you really want to train for an "iron head" skill?
- Adjustability: Everyone's nose has a different height and width. If the nose pads are not adjustable, the fit will be very poor.
Sunglasses Maintenance
Proper maintenance of sunglasses ensures they stay clean, undamaged, and extends their lifespan.
- Cleaning sunglasses: Gently wipe the lenses with a soft cloth or a special eyeglass cleaning cloth. Avoid using rough paper towels or clothing to prevent scratching the lenses. For a wet wash, you can put a couple of drops of a non-alkaline detergent on the cleaning cloth and then gently wipe. Avoid using cleaners containing alcohol or solvents, as they may damage the lenses.
- Avoid touching the lenses: Try to avoid touching the lenses with your fingers, as dirt and oils can leave fingerprints or stains. If you need to adjust the position of your sunglasses, it's best to hold the temples with both hands.
- Storing sunglasses: When not wearing your sunglasses, store them in a dry, clean place, preferably in a special sunglasses case or bag to protect them. Avoid placing sunglasses in pockets or bags without protection to prevent scratching or impact with other items.
- Avoid high temperatures and humidity: Avoid exposing sunglasses to high temperatures or humid environments for extended periods, as this may cause the lenses to deform or the coating to be damaged. Try not to leave sunglasses on the car dashboard or exposed to direct sunlight.
- Repair damage: If the sunglasses are damaged, such as loose screws or broken temples, it's best to take them to a professional eyewear shop or manufacturer for repair. Attempting to fix them yourself may cause further damage to the sunglasses.
- Avoid prolonged immersion in saltwater: If you use sunglasses for water activities, try to avoid immersing them in saltwater for long periods, as the salt can damage the lenses and coatings. After use, rinse the sunglasses with fresh water and then dry them with a dry, clean cloth.
5. China's Eyewear Industry Belt
China hosts several eyewear production bases and distribution centers, among which Jiangsu Danyang, Guangdong Shenzhen, Fujian Xiamen, and Zhejiang Wenzhou are the four major eyewear production bases in China.
- Jiangsu Danyang
Main Products: A complete industrial chain, producing 100 million pairs of frames annually, with lens production accounting for 75% of the national output.
Market Positioning: Mid to low price range, mass production at affordable prices.
- Zhejiang Wenzhou
Main Products: Primarily frames, with some lenses.
Market Positioning: Mid to low price range, focused on exports.
- Fujian Xiamen
Main Products: Frames, mid to high-end sunglasses frames.
Market Positioning: Mid to high price range.
- Guangdong Shenzhen
Main Products: Boutique glasses, OEM for overseas markets.
Market Positioning: High-end pricing, closely connected to Hong Kong and Macau markets.
