Doctors who heal the sick are known as "angels in white", a title that has become synonymous with medical workers. Have you noticed that surgeons change into green surgical gowns during operations? Why are these gowns not white?

During most of an operation, surgeons focus intently on bright red tissues and organs. This can easily lead to visual oversaturation. When the brain is continuously exposed to the same visual stimulus, nerve fatigue sets in. As the surgery goes on, the eyes gradually lose the ability to distinguish subtle shades of red. Therefore, surgeons need to glance at green objects from time to time to maintain their sensitivity to red.

You may wonder why white or other colors cannot serve the purpose. The reason is simple: surgeons are constantly looking at bright red blood. If medical staff wear white coats in the operating room, after a while, a surgeon shifting their gaze to a colleague's white coat will see scattered "green bloodstains". White surgical attire can easily cause afterimage optical illusions, which pose great risks to patients undergoing surgery.

This is a phenomenon called persistence of vision, also known as visual afterglow. When people look at an object and then shift their sight elsewhere, the eyes retain the image of the original object for about 0.1 to 0.4 seconds. The stronger the visual stimulus or the more fatigued the eyes are, the longer the afterimage lasts. To relieve fatigue, the optic nerves produce complementary colors as a form of self-regulation.

Scientists have conducted a simple experiment. Coat a white cloth with bright red paint. Stare at the red cloth for a while, then look at another plain white cloth, and you will see a pale green shape identical to the original red cloth. This afterimage takes several seconds to fade away. Pale green is the complementary color of red, which explains why it is chosen for surgical gowns. This color eliminates green visual illusions caused by complementary colors, sharpens surgeons' perception of red, eases optic nerve fatigue, ensures smooth operations and prevents medical incidents.

From the perspective of stain resistance, blood is inevitable in all surgeries, major or minor. Blood splatters stand out prominently on white or other light-colored gowns. The sight may make patients nervous and scared, and also disturb surgeons, who will perceive the gowns as heavily contaminated and unwearable.

Green and teal, the contrasting colors of red blood, are used for surgical gowns. Blood splatters on these fabrics appear dark brown rather than vivid red, softening the visual impact. Besides, teal helps calm people mentally, keeping surgeons focused during operations. As a symbol of vitality, green also brings patients hope for survival.

Even if you have never been inside an operating room, you may notice that operating room walls in movies are painted light blue or solid green. This is not for disinfection or mere decoration. It follows the same principle as the color choice for surgical gowns, and is fully backed by scientific evidence.