Researchers have found that people with bloodshot eyes are considered sadder, unhealthier and less attractive than those whose eye whites are untinted, a cue which is uniquely human, the`Ethology`journal reported.
"Red, `bloodshot` eyes are prominent in medical diagnoses and in folk culture. We wanted to know if they influence the everyday behaviour and attitudes of those who view them, and if they trigger perceptions of attractiveness," said lead author Robert Provine of University of Maryland.
Bloodshot eyes occur when the small blood vessels of the usually transparent conjunctiva membrane on the surface of the eye become enlarged and congested with blood, giving a red tint to the underlying sclera, the "white" of eyes. Redness of the sclera is believed to be a general but important sign of a person`s emotional and biological state.
In their test to find out perceptions and behavioural implications of red eyes, the researchers examined more than 200 volunteer students, composed of 93 males and 115 females,with an average age of 20.6 years.
The volunteers were shown 200 images of eyes, half with clear white sclera and half with sclera tinted red by digital image processing. The volunteers were asked how sad, healthy or attractive the owners of the eyes were The results revealed that people with reddened eyes appear sadder, less healthy, and less attractive compared to those with whiter, untinted eyes.
This is the first study to show that eye redness is perceived as a cue of emotion, Provine said.