Eye surgery and lower the risk of infection. These precautions include the use of antiseptics, such as povidone-iodine, and sterile drapes, gowns and gloves. Although the terms laser eye surgery and refractive surgery are commonly used as if they were interchangeable, this is not the case. Lasers may be used to treat nonrefractive conditions (e.g. to seal a retinal tear). Laser eye surgery or laser corneal surgery is a medical procedure that uses a laser to reshape the surface of the eye. This is done to correct myopia (short-sightedness), hypermetropia (long sightedness) and astigmatism (uneven curvature of the eye's surface). It is
Effect of spaceflight on the human body experienced by humans in the initial hours of weightlessness is known as space adaptation syndrome or SAS, commonly referred to as space sickness. It is related to motion sickness, and arises as the vestibular system adapts to weightlessness. Symptoms of SAS include nausea and vomiting, vertigo, headaches, lethargy, and overall malaise. The first case of SAS was reported by cosmonaut Gherman Titov in 1961. Since then, roughly 45% of all people who have flown in space have suffered from this condition. The duration of space sickness varies, but rarely has it lasted for more than 72 hours, after which the