1. History Of Surgical Lights
Before electricity allowed lightbulbs to illuminate an operating room, candles were used as a light source during a procedure. Additionally, surgeries were performed during daylight hours so surgeons could use the natural sunlight for illumination.2 Surgical lights as they are recognized today have evolved over more than a century since electricity was first discovered in 1879, with surgical light manufacturers continuously working to improve lighting conditions for surgeons and OR staff.
2. What Is a Surgical Light?
Surgical lights are referred to by many names: Operating lights, OR lights, operating room lights, surgical lamps, and surgical light heads. Surgical lights are medical equipment devices used to illuminate the operating field during surgery. A group of surgical lights providing lighting in the operating theatre is often referred to as a surgical light system. They have mainly been used in hospital operating rooms and ambulatory surgery centers, but can also be used in various locations throughout the facility to provide high-quality lighting for procedures.
3. Types Of Surgical Lights
Surgical lights can be categorized based on the light type as either incandescent (conventional) or LED lights. Conventional surgical lights are basically gas-filled incandescent lights that contain halogen at a certain pressure setting. Light-emitting diode (LED) lights have been a revolutionary improvement in the field of surgical lighting, virtually eliminating the problem of infrared radiation caused by excessive heat. Surgical lights can also be categorized based on mounting configurations such as ceiling-mounted, on-floor or portable lights, and wall-mounted lights.
4. What Is Important In a Surgical Light?
When shopping for surgical lighting, there are a few key terms you need to know: Illumination, color temperature, color rendition index, light field diameter, lifespan, etc.
* Illumination
Illumination refers to the light intensity output of the surgical light head, which is measured in lux. The standard distance for measuring lux on a surgical light is a meter. Most lights don’t produce light intensity beyond 160,000 lux, and lights that measure under 40,000 lux aren't considered fit for surgical use.
* Color Temperature
Color temperature is measured in Kelvin, and it refers to the overall color produced by the light source. Warm colors like red and yellow are at a lower Kelvin temperature, whereas white and blue are higher. Daylight is considered approximately 5,800 Kelvin. When you're searching for surgical lights, make sure they can deliver within the 3,000 - 6,700 Kelvin range.
* Color Rendering Index (CRI)
The CRI measures the quality of light produced, as related to perfect visualization. Bright daylight is considered the optimal light for viewing the natural color of objects and has a CRI of 100. Make sure the surgical lights you choose have a CRI between 80 and 100.
* Lifespan
Surgical lights manufactured today typically last for 40,000 to 60,000 of use, but this number isn't as straightforward as it seems. Most surgical light lifespan estimations are calculated to measure how long a light will produce up to 70 percent of its original output, not how long it can deliver full intensity. It's important to be aware of this discrepancy when researching surgical lights for your facility.
* Shadow
Shadows are cast from the surgeon’s head, arm, or body as well as the surrounding medical team during the surgery. The latest lights use multiple light sources that can be easily cross-focused to virtually eliminate shadows.
* Radiating Heat
Traditional lighting systems produce higher levels of heat which can cause discomfort for the surgeons and dry out exposed tissues, potentially impacting patient care and recovery. Heat radiation also interferes with the laminar airflow in operating rooms, which helps to reduce bacterial organisms in the surgical area by generating continuous bacteria-free airflow in a certain direction. Filters and lenses are often employed, which allow light but block heat emissions. LED surgical lights are a good investment since they produce virtually no heat, while on the other hand, halogen lights dissipate much higher levels of heat.
* Surgical Light Field Diameter
Surgical lighting should have the ability to adjust to a wide range of light fields. A light field diameter of D10 is the diameter of light field around the light center, where the illumination is 10 percent Ec. A light diameter of D50 should not exceed 50% of a D10 diameter. The illustration below represents this functionality. The smaller arrow is D50 while the larger arrow is D10. This simply means that 50 percent of the entire pie of light intensity should fall within 50 % of its total diameter.
* Sterilization
For obvious reasons, all surgical lighting equipment should be easy to clean and disinfect. If lighting includes straps or an adjustment apparatus, it should be antibacterial. All lighting equipment should be free from unnecessary crevices, as these can harbor bacteria.
* Extras
Do you need cameras? Monitors? Sterilizable handles? Make sure you factor those into your purchasing decisions.
5. How Much Do Surgical Lights Cost?
The costs of surgical lights range from $6,000 for low-end models that use a single-halogen lamp to $40,000 for the most expensive systems that may include LED lights and are wired for in-light cameras and have display arms for video monitors.
6. Summary
Surgical lighting is complex, sophisticated, and often customized for an OR. For that reason, the purchase of this equipment is a multi-step process to ensure that the right equipment is acquired to perform successful and safe procedures. The new standard in surgical lighting can help organizations meet this goal and avoid known pitfalls. Using LED systems that emit white pure light will allow surgeons to assess and interpret the anatomical appearance of the surgical cavity accurately and consistently. Auto intensity functionality helps surgeons better discern between a spectrum of deep, saturated reds precise contrast and definition needed for superior tonal definition. A uniformed beam eliminates hot and cold spots and reduces eye fatigue.
Technical and operational guidelines for surgical and examination lights.
| Requirement | Examination lights | Surgical lights |
| Illuminance (lx) | 1,000 | 40,000 – 160,000 |
| Color rendition (CRI) | 85 – 100 | 85 – 100 |
| Color temperature (K) | 3,000 – 6,700 | 3,000 – 6,700 |
| Shadowless | No | Yes |
| Sterilizable handles | No | Yes |
References
Dumbleton, T., Clift, L., Clift, M., Bayer, S., Elton, E., Howarth, P. and Maguire, M. (2010). Buyer's guide: Operating Theatre Lighting. London: NHS Purchasing and Supply Agency.
Morgan-Hughes, J. (1968). Lighting and Cyanosis. British Journal of Anaesthesia, 40(7), pp.503-507.
