Usually, people can’t recognize or feel UV light, it is a kind of invisible light, but it can be unknowingly absorbed by the skin and eyes and other organs and cause damage, known as the “invisible killer” is not too much. If the skin peeling and sunburn caused by UV light can be used as a warning to draw attention, then the damage caused to the eyes is not obvious in the early stage and is not easy to attract attention. The eye is the most sensitive organ to UV light, which mainly causes damage to the cornea, lens and retina of the eye. Studies have shown that UV light with a wavelength of 280 millimeters is the most damaging to the cornea, causing severe pain, corneal clouding and loss of vision, resulting in solar keratitis. Near ultraviolet rays with wavelengths of 290-400 millimeters can cause damage to the lens, which is one of the causative factors of senile cataract. According to data published by the World Health Organization, 16 million people worldwide are blinded by cataracts each year, and 20% of them are caused by long-term exposure to UV light. Ultraviolet light, especially long-wave ultraviolet UVA, can penetrate deep into the eye and reach the fundus of the eye to cause macular degeneration and other retinal pathologies. UV radiation exists all year round, and its damage to the eyes has a cumulative effect, so preventive measures should be started early to protect the eyes from UV damage. Children’s eyes in particular are more sensitive to UV radiation, and the amount of incident UV radiation that can pass through the clear lens of children 10 years of age and younger is 6.5 times greater than that of adults, making eye UV protection more significant for children. Most children are exposed directly to UVB without any protection when they are outdoors. Parents should instruct their children not to look directly into the sun to ensure that children’s eyes are in a protected state, laying the foundation for a lifetime of visual health. Reducing sun exposure and proper eye protection are the two main principles for avoiding UV damage to the eyes. Between 11 a.m. and 2 p.m., when the sun is directly overhead, the amount of UV radiation is strongest. When outdoors during the day, pay attention to the UV rays brought by the reflected light from the road surface, water, snow and beach, especially the glass curtain wall of the city building produces a lot of glare and scattered light, these UV rays belong to the stronger amount of radiation, causing greater damage to the eyes, but it is easy to be ignored. Sunglasses are not only needed in the summer, but can actually be used all year round. You should wear sunglasses marked with “100% UV protection” “UV400”, which means that the lenses can block all UV rays below a wavelength of 400 millimeters and can achieve the effect of protection against all UV rays. According to the principle of optics, the color of the lens is better in gray, brown and dark green, which can retain the most natural original color when seeing things, and is a good choice. Wearing unqualified sunglasses without UV protection, the human pupil will be dilated, UV light is easier to enter the eyes than when not wearing sunglasses, the damage to the eyes can be imagined, long time wearing may cause vision loss. So you can’t just focus on the style, but ignore the quality of the sunglasses themselves.