Reducing visual fatigue
in the OR

High-contrast lighting can contribute to fatigue-related errors

It is important for hospitals to choose an OR light which can reduce strain, minimize fatigue, and improve surgical outcomes.

For decades, it’s been known that very high contrast in the workplace has been shown to inhibit task performance (Stone, 1980) [1]. This is particularly significant in a surgical setting. Understandably, illumination must be bright and focused at the surgical site. Modern surgical lights provide a light field of approximately 20 cm in diameter, with illumination of up to 160,000 lux – brighter than a sunny day at the beach. The ambient lighting in the room rarely exceeds 1,000 lux. The contrast between the brightly illuminated light patch and the surrounding area is too dramatic, resulting in discomfort and eye strain. Studies have shown that one-third of surgeons suffer from visual fatigue, leading to poor posture and physical strain that can compromise the surgeon’s performance (Hemphälä, 2009) [2].

Identifying visual preferences for contrast ratios

In 2013, a study was conducted to identify the visual preferences of 50 participants to determine the best contrast ratios.

Six illumination scenarios were presented. In each test, the main surgical light was controlled independently to maintain high quality illumination on the surgical site. Varying amounts of additional light were added to create different levels of contrast in the light patch periphery.

Transitional lighting improves comfort and visual acuity

The nature of surgical lighting is that the primary light patch and the transitional lighting must always be concentric. To achieve this goal, the transitional light must be mounted within the same light head, encompassing a broader area surrounding a shared central axis.