Infrared heat may be a hot new trend in grilling, but this type of heat has been occurring naturally since the dawn of time. In fact, everything with a temperature above absolute zero (which is equal to -459.67 degrees Fahrenheit or -273.15 degrees Celsius) emits at least a little infrared radiation.
For example, bacterial and viral causes of pinkeye are almost always contagious and are spread from person to person. However, pinkeye caused by allergens and chemical irritants is not contagious by person-to-person contact. Pinkeye that is contagious has an incubation period as long as 14 days. However, most doctors do not think that pinkeye becomes contagious to other people until symptoms start to develop.
Pink eye also can be caused by bacterial conjunctivitis, which  even with treatment such as prescription antibiotic eye drops  can last up to a month or longer. However, with this type of pink eye, people should no longer be contagious 24 hours after antibiotic treatment begins.ommon pink eye symptoms can last anywhere from a few days to a few weeks. Many types of pink eye are contagious, but only after the symptoms emerge.