The color palette of an operating room (OR) is a deliberate choice rooted in human visual science. While the historical image of a surgeon involves white garments, modern surgical environments are characterized by shades of green, blue, and teal. This shift from white to cooler colors is a functional design decision intended to reduce visual fatigue and improve focus, and enhance the safety and precision of medical procedures. The colors surrounding the operating field are a form of visual ergonomics to support the intensive concentration required of the surgical team.
The Visual Strain of White Operating Rooms
In the early 20th century, all hospital settings, including operating rooms and surgical attire, were predominantly white to symbolize cleanliness and sterility. However, this high-contrast environment created significant problems for the surgical staff’s vision under intense lighting. The powerful, focused lamps necessary to illuminate the surgical site reflected harshly off the white walls and scrubs, causing glare. This reflected light contributed to eye fatigue, which could impair a surgeon’s performance during long procedures.
The second major issue was the stark contrast between the bright white surroundings and the deep red of the patient’s blood and internal tissues. Staring intensely at the red surgical field, then glancing up at a white surface, was visually jarring. This rapid shift in light and color intensity forced the eyes to constantly re-adapt, accelerating visual strain and discomfort. This practical problem led to the search for a color that could neutralize the visual effects of the red surgical field.
How Complementary Colors Reduce Visual Fatigue
The solution lies in the physiological mechanism of color perception and complementary colors. Red and green are opposites on the color wheel, making them complementary colors. This opposition is directly relevant to how the human eye processes color information.
When a surgeon spends a long time focused on the red tissues, the photoreceptor cells in the retina responsible for detecting red light become temporarily overstimulated and desensitized. If the surgeon then shifts their gaze to a blank white surface, the red cones are slow to recover, while the green and blue cones remain fully sensitive. The brain interprets this imbalance as seeing the complementary color, resulting in a brief, distracting green or cyan “afterimage” on the white background. This visual illusion can be disorienting and momentarily obstruct the surgeon’s view.
By changing the OR environment to green, a surgeon looking away from the red field will see the green afterimage blend into the green background. This blending immediately neutralizes the visual disturbance, allowing the red cones to reset without creating distraction. Looking at the complementary color also helps maintain the eye’s sensitivity to variations in red, which is crucial for accurately distinguishing different shades of tissue and blood during the operation. The use of green or blue acts as a visual reset button, improving the surgeon’s ability to focus and discern fine detail.
Why Modern ORs Use Blue and Teal
While the initial shift was to green, modern operating rooms use shades of blue, teal, or cyan for the walls, drapes, and surgical scrubs. These colors are all near-complements to red on the color wheel and serve the same physiological function as green. Blue and teal colors are less jarring and more calming, contributing to a tranquil environment for the surgical team.
Blue-green hues are also used in the surgical field. Surgical drapes and gowns are colored blue or teal to ensure a consistent, low-contrast visual field around the patient. This consistency minimizes glare and reduces eye strain, allowing the visual acuity gained from the complementary color effect to be maintained throughout the procedure. This selection ensures the surgeon’s primary focus remains on the highly-lit surgical area, with the surrounding environment providing a restorative backdrop.