Facts You May Ignore About Harmful UV Rays

by BrightDr. on Aug 08, 2022

Facts You May Ignore About Harmful UV Rays
Studies have found that nearly 30% of solar radiation penetrates the atmosphere, especially UV rays with wavelengths greater than 315 nanometers are the most damaging to the eyes; therefore, good sunglasses must reduce light transmission and filter out more than 90% of visible light.

Gray lenses are effective, and the choice of lens color also matters for eye protection. President Wang Hong said that gray and teal lenses have the best eye protection effect, especially gray lenses with good light transmission, the most balanced all color, is the most natural tone, calm and gentle. The common dark green lenses are less, the clarity is not as good as the light gray lenses after wearing them. Luminous anti-glare, in dark occasions or driving at night, it is recommended to wear yellow lenses, which can filter some of the light. Blue and pink lenses sunglasses to avoid wearing, blue lenses will block blue light, the most will absorb light and hurt the eyes blue light is the main cause of retinal macular degeneration, choose sunglasses, blue lenses not only can not block blue, indigo, purple three colors of visible light, but also will attract these harmful blue light through the eyes, the worst effect of eye protection.

We also do not recommend the use of black lenses, because it has a masking effect on all colors, unless the eyes are photophobic after surgery, otherwise it is more dangerous to wear black glasses in daily life to see things in a dead angle. It is important to note that sunglasses are not "exclusive" to adults. Anyone's eye lens can suffer from cataracts and even blindness due to long-term intense sunlight. Therefore, eye protection should be done from a young age.

Children need to wear sunglasses. 2. People with light skin tone. 3. People who are sensitive to light. 4. Drug-related photosensitivity. 5. Post-operative eye disease, contact lens wearers. 6. Locations with particularly strong UV rays. 7. Outdoor workers. Effects of UV light on the eye

Effect 1: When the eyes are exposed to the hot sun for a long time, the first to be affected is the black eye. If a large amount of exposure to the sun, it will cause injury to the cornea, and patients will immediately experience pain, discomfort, and watery eyes. Effect 2: Secondly, the crystalloid is damaged. Long-term exposure of the eye to UV light will break the chain of the crystalloid, which is evenly distributed in the loess, into an irregular shape, reducing transmittance and affecting vision. Effect 3: The retina is also affected by UV light. The retina is located at the back of the eye where the nerve is located. Once damaged, it cannot be restored and is generally called macular depilatory disease.

For UV, when its wavelength is shortened, the ability to pass through the cornea is also reduced, but the absorption rate is significantly increased. Half of the remaining 98% is absorbed by the corneal epithelium and half by the interstitium. If the wavelength continues to drop to 230nm, then 97.3% is absorbed by the epithelium and almost nothing enters the eye.

UV damage to the eye is mainly caused by short-wave (far) UV. It is generally believed that the damage to the cornea is greatest when the wavelength of ultraviolet light is 280nm, while the effect is relatively reduced when the wavelength is above 310nm or around 254nm. The literature points out that the most effective wavelength for the cornea is 288nm, while the best absorption rate of corneal epithelium is 265nm, which is the absorption wavelength of nucleoprotein. Therefore, the UV radiation acting on the cornea is far (short-wave) UV radiation with wavelengths below 320 nm. Electrophthalmic uveitis is the result of exposure to short-wave UV light and is the most common occupational eye disease. Its early symptoms include severe pain, photophobia, eyelid spasms, tears like fountains, light exposure to the eye, aggravation of the condition, examination of the eye reveals congestion, facial flushing, diffuse punctate clouding of the cornea, positive fluorescein staining, decreased corneal perception, and spasmodic narrowing of the pupil.

The UV light that damages the crystal is long-wave UV light (near UV light) with wavelengths of 400 nm to 320 nm, which is mainly absorbed by the crystal. However, animal tests have proven that only high doses of UV light sufficient to damage the cornea can damage the crystal.

Short-wave UV damage to the eye is also seen in snow marching, mountain climbers and staff in the desert and sea tropics, often referred to as solar ophthalmia (snow sickness), the symptoms of which are very similar to electrophthalmia.

From an epidemiological survey, the incidence of senile cataracts is higher in tropical areas than in temperate areas. Some experts in China have analyzed the incidence of cataract in seven rural areas, which is related to regional latitude, altitude and ultraviolet content in sunlight, and ultraviolet radiation is closely related to cataract formation.

Ultraviolet radiation can also cause retinopathy, which was discovered by Guerry and Ham in 1982 that heliophthalmia and eclipse are actually photochemical effects caused by near ultraviolet light on the retina, not thermal burns.

Leave a Comment

Your email address will not be published.