Mercury (element) is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps and other devices, though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alternatives such as alcohol- or galinstan-filled glass thermometers and thermistor- or infrared-based electronic instruments. Likewise, mechanical pressure gauges and electronic strain gauge sensors have replaced mercury sphygmomanometers. Mercury remains in use in scientific research applications and in amalgam for dental restoration in some locales. It is also used in fluorescent lighting. Electricity passed through mercury vapor in a fluorescent
Toxic and nutritional optic neuropathy neuropathy, vision generally recovers to normal over several days to weeks, though it may take months for full restoration and there is always the risk of permanent vision loss. Visual acuity usually recovers before color vision. In industrialized nations, toxic and nutritional optic neuropathy is relatively uncommon and is primarily associated with specific medications, occupational exposures, or tobacco and alcohol abuse. However, in developing nations, nutritional optic neuropathy is much more common, especially in regions afflicted by famine. Both genders and all races are equally affected, and all ages are susceptible. Toxic and nutritional optic neuropathy Toxic and nutritional optic