The aim, says Han, is to enable family doctors to easily identify patients who are ageing prematurely. If the cause can be identified, such as smoking, overeating or lack of exercise, people can then take action.

Han and his colleagues analysed 3D facial images of 332 Chinese volunteers between the ages of 17 and 77. They identified several features that significantly change with age, such as the slope of the eye, the distance between the mouth and the nose, and the smoothness of skin.

They used this information to create a composite map of the human face as it ages and compared each participant’s 3D image with the map. This revealed that on average, facial age differed by about six years either way of real age. The difference between real age and facial age increased after volunteers hit 40.