Basic knowledge of sunglasses: uv damage to the corneal and conjunctival

Sunglasses in addition to can reduce the radiation intensity of visible light, can also reduce the ultraviolet and infrared radiation. Sunglasses cash more endowed with fashionable breath. But the fundamental role of sunglasses is to provide radiation protection for the eyes. Sunglasses are introduced in this paper the basic knowledge of uv damage to the lens. To travel to the surface of the ultraviolet radiation is restricted by many factors, such as season, latitude, altitude, climate, sunshine time, the surrounding environment on the reflectivity of ultraviolet (uv) radiation, etc. With the solar zenith Angle, ozone concentration, cloud, surface reflectivity is important. Surface ultraviolet radiation of ultraviolet radiation that is not the same as the lens. Human activities such as personal habits, length of time of outdoor activities and professional on eye ultraviolet (uv) radiation is obvious, the influence of other factors can also affect the eye ultraviolet radiation. The degree of tissue damage a dose-dependent relationship, that is, the longer the irradiation time, the greater the dose, the more serious the cause of damage. Ultraviolet radiation causes the damage of the eye including cornea, conjunctiva, turn film, lens, related epithelial injury. Ultraviolet radiation damage to the lens: cataract is significantly related to the ultraviolet (uv) radiation exposure of visual damage, excessive ultraviolet spider is considered to be the main cause of cataract increase. Ultraviolet (uv) radiation damage in the lens comes mainly from photochemical reaction, the direct effect of photochemical reaction is the tremendous amount of antioxidant and other sources of oxidant and antioxidant substances can be more or less uv radiation damage effect. Have a lot of melanin granules in the iris, can protect behind the iris lens tissue from ultraviolet radiation damage, so the color of the iris of the lens of the ultraviolet (uv) radiation has a great impact. The other part of aqueous humor can absorb ultraviolet (uv) radiation, and has a lot of antioxidant system in aqueous humor, can counteract oxidant in the ultraviolet (uv) radiation, so the anterior chamber depth on the lens of the ultraviolet irradiation quantity also has a great influence. Crystal absorption peak at 280 nm to 300 nm band, belong to UVB rays. Due to the band of absorption rate is very high, so in the case of radiation is not very strong remains possible damage to the human eye lens. Ultraviolet (uv) radiation is nonionizing light, can produce effect after being absorbed, energy is cells nucleic acids, proteins or other molecules absorbed, some energy is converted into thermal energy dissipation, and the other part is changed the spatial structure or some macromolecular chemical bonds, the harm of ultraviolet radiation on the organism mainly damaged proteins and DNA, causing cell damage. By ultraviolet irradiation cell after DNA damage, can cause the protein synthesis of a series of change, leading to cell function change, the position of the lens. Ultraviolet (uv) radiation effect on DNA and enzymes lens on the lens protein, after UVB exposure, reconstructing lens proteins, but its higher turbidity. Lens protein is rich in tryptophan, tyrosine and phenylalanine, such as amino acid, due to absorb the ultraviolet, generate a large amount of oxidant, lead to the higher the lens tissue oxygen damage, produce a cataract. Caused by ultraviolet (uv) radiation cataract is cortical cataracts, and crystal turbidity show the cortex of the lens portion of the nasal side more than the temporal side: nasal below 57%, the temporal below 22%, the temporal above 13%, nose above 8%. This may be above and ultraviolet radiation from the temporal, the below the eye refractive system focused on the nose. Next we introduce basic knowledge of sunglasses uv damage to the choroid and retina.