A study carried out by the University of Granada has scientifically shown that alcohol consumption significantly worsens night vision . This occurs because alcohol increases the perception of halos (luminous circles) as well as other nocturnal visual disturbances that lead to poor vision.
The study, which has been published in the Journal of Ophthalmology , explains that alcohol impairs the optical quality of the image we see because it deteriorates the tear film that covers the surface of the eye ; This occurs basically because the ethanol from alcoholic beverages reaches the tear and acts as a solvent for the outermost layer of the tear film, thus evaporating the watery part of the tear. Thus, with this temporary wear of the tear film, our image quality is also poor.
To reach this conclusion, the researchers conducted an experiment with 67 participants in which the BAC in breathed air was measured with an ethyl meter after consuming various amounts of alcohol and performing night-time visual performance tests (halometer). The results showed that alcohol consumption increased the perception of halos and other visual disturbances, as well as the deterioration of the optical quality of the image provided by the eyes of the participants . This last aspect was especially noted in the subjects who achieved an alcohol level greater than 0.25mg / l, that is, the legal rate allowed in Spain in terms of driving.
“This research offers very useful results for society and public health, especially in night driving, since alcohol consumption and low lighting conditions are two aspects that are present in many traffic accidents, so society must be aware with the effects that alcohol consumption produces, especially on vision, ”says José Juan Castro Torres, leader of the study.
