Mark Gaston, SSL product manager at Excelitas, said any conversation about lighting is going to start with a crash course in LEDs. These computer chips emit energy in the form of light, which is sourced from electricity.
While LED manufacturers have the ability to manufacture high color rendering index (CRI) LEDs, which offer improved color performance, not all manufacturers have adopted the technology due to increased design complexity and affordability, according to Gaston. During the purchasing process, certain industry terms are used to describe the light LEDs provide. Here’s the breakdown.
- Lux: Measurement of brightness. One lux is the equivalent of one lumen per square meter. For some perspective, sunlight ranges from 32,000 to 100,000 lux, and a normal office light is about 400 lux. The brightest surgical headlamps on the market are about 200,000 lux. When measuring lux, distance is a critical value, and most headlamps are measured at 14 inches. Overhead surgical lights are typically evaluated a few feet out.
- Kelvins: Measurement of color temperature. The goal for manufacturers is to create an LED as pure white as possible. Some of the purest white headlamps are about 6,000 degrees Kelvins, which created a temporary problem for surgeons. Surgeons said light cast by headlamp LEDs was too pure and did not offer the tint fiber optic bulbs had when they got hot. The xenon bulbs tinged everything a cooler blue and halogen bulbs made everything look a warmer yellow. Suppliers fixed this problem with filters.
- CRI: Evaluation of the color purity. Different color LEDs can be combined to achieve a higher overall CRI, but that typically means more cost.
This article was featured in the November/ December 2015 issue of Surgical Products. To see the complete issue, click HERE.