To find out if you are infected with a virus instead of simply measuring your forehead temperature with a thermal scanner first measure the temperature of the upper inner corner of your eye socket then measure the temperature of your fingertip. The greater the difference in temperature between the two, the more likely you are sick
But with fever, deep body temperature increases while the hands get colder, so the difference between the eye and finger temperature increases. Therefore, a more accurate way of using infrared thermometers to screen for COVID-19 might be to measure the temperature of the hand and the corner of the eye and determine the difference.
This wouldn't be perfect. Other situations can also increase this difference, including some age-related conditions. And, as we've noted, not all infected people develop fever symptoms. But it would be a step in the right direction, and so is worthy of further consideration.
