The brown light reflection in the anterior chamber of the ocular lens, thought to be a “mercury lensitis” caused by mercury deposition, can persist after symptoms of poisoning have disappeared or after exposure to mercury has been removed, and is another marker of mercury absorption. What can cause mercury poisoning? I. Etiology 1. Occupational factors (35%) Mercury poisoning is a common occupational poisoning because mercury is rich in mobility and evaporates easily at room temperature. It mainly occurs in the production of long-term inhalation of mercury vapor or dust of mercury compounds. Production poisoning is seen among production workers in mercury mining, amalgam smelting, gold and silver extraction, vacuum mercury, lighting lamps, meters, thermometers, dental fillings, mercury thunder, pigments, pharmaceuticals, nuclear reactor coolant and anti-atomic radiation materials, etc. 2.Environmental factors (30%) Mercury exists widely in nature, and various natural phenomena can make mercury circulate continuously from the surface of the earth through the atmosphere, rain and snow, and can be absorbed by plants and animals. Human production activities can significantly increase the pollution of the environment by mercury. Although the proportion of such anthropogenic pollution is not very large, but the emission is concentrated, so the harm is far more serious than natural pollution. Mercury-containing sewage pollution of rivers, lakes and seas can cause public health problems, such as Minamata disease. 3.Misuse factor (10%) Short time (>3~5 hours) inhalation of high concentration of mercury vapor (>1.0mg/m3) and oral intake of large amounts of inorganic mercury can cause acute mercury poisoning; taking or applying mercury-containing prescriptions can cause sub-acute mercury poisoning; occupational exposure to mercury vapor often causes chronic mercury poisoning. Mercury ions can easily combine with sulfhydryl groups to make cytochrome oxidase, pyruvate kinase, succinate dehydrogenase, etc. inactive, and mercury also combines with amino, carboxyl and phosphoryl groups to affect the activity of functional groups. In recent years, it has been found that mercury damages the kidney, mainly the epithelial cells of the renal proximal tubule, and mercury can also cause immune dysfunction, autoantibodies and nephrotic syndrome or glomerulonephritis.