A new device called Thermoglaz thermal indicator has been invented to quickly identify patients with fever, including those infected with COVID-19 and other viral diseases. The device is made in the form of a human eye and changes color from pink to white with increasing temperature. Those who are not provided with an indicator are required to maintain quarantine of home self-isolation. If a person with the indicator is found nearby, changing color from white to black, indicating an average elevated temperature characteristic of the virus, or changing color with an “eye socket” around a black “pupil”, indicating a high temperature, measures are taken to detain him and deliver him to a medical institution for appropriate treatment. The device can be controlled with a mirror without removing it.