In a hospital setting, various areas pose potential risks, but the operating rooms are particularly tense and critical. It is within these rooms that surgeons, with scalpels in hand, work under the illumination of powerful lights, striving to save the lives of patients on the stretcher. Considering this, ensuring optimal OT lighting becomes absolutely crucial. It is one of the fundamental elements necessary for surgeons to perform their work with confidence and precision in a medical setting. In this blog, we will provide you with basic information about LED OT lights.
What Are LED OT Lights?
LED OT lights, shorthand for LED operation theatre lights, are also referred to as LED surgical lights. They are extensively employed in ambulatory surgery centers and hospital operating rooms. Moreover, their application extends beyond these settings, as they can be utilized in various areas within medical facilities to ensure superior lighting during procedures, including emergency rooms, labor and delivery rooms, examination rooms, and any setting where medical procedures are conducted. Incisions and body cavities are illuminated with these lights by clinicians, surgeons, and proceduralists so that they can observe small, low-contrast objects at different depths at the surgical site. Given their significance in surgical operations, LED OT lights represent an indispensable medical tool that practitioners in the medical field must be well-acquainted with.
What Is the Working Principle of OT Lights?
When a cylindrical tube is placed on a table and a single candle is lit next to it, a clear shadow is formed. If two candles are placed next to a tea cone, two overlapping shadows are created, with a completely dark region called the umbra and a partially lit region called the penumbra. The size of the umbra decreases as the light source becomes larger. By applying these principles, scientists have developed shadowless OT lights for surgery.
These lights consist of a circular arrangement of high-intensity lamps on a panel, creating a large and uniform source of light. This design allows the light to be projected from multiple angles onto the surgical table, ensuring sufficient brightness without causing noticeable shadows. So the term “shadowless” is used to describe these OT lights. The aim is to provide surgeons with optimal visibility during procedures by minimizing shadows and maintaining a well-illuminated surgical field.
The History of OT Lights
In the 1920s, Professor Weyland from France invented the first surgical OT light in England. This early design featured a 100-watt bulb positioned at the center of a refractive lens, which was constructed using multiple narrow glass plates arranged evenly on the dome of the operating lamp. The resulting cone-shaped OT light eliminated spires.
The next advancements in OT lights came in the 1930s and 1940s with the introduction of the single dome type ceiling OT light in France and the track type OT light in the United States. During this period, incandescent bulbs were used as the light source, but they had limitations in terms of wattage, with a maximum of only 200 watts. The large area around the filaments made it difficult to control the direction of light, resulting in poor focus. The reflectors used were made of copper and lacked reflectivity, further affecting the shadowless effect of the OT light.
By the 1950s, hole-type multi-lamp OT lights had been created and were being utilized in Europe and Japan to enhance illumination. This design increased the number of light sources and utilized small reflectors made of high-purity aluminum, significantly enhancing the lighting performance. However, the increased number of light bulbs in this design can cause a rapid rise in temperature, discomforting the surgeons and drying out the tissue at the surgical site, which is bad for the patient’s post-operative recovery.
In the early 1980s, Japan introduced cold light hole-type surgical shadowless lamps utilizing halogen light sources. Then in the late 1980s and early 1990s, overall reflection halogen OT lights were created using computer-aided design (CAD) methods to manufacture reflector surfaces. These reflectors were formed using industrial stamping, resulting in multidirectional reflectors. This surgical light source gives a good shadow-free quality in addition to being as bright as daylight.
Approaching the 21st century, OT lights have been continuously improved. Improvements have been made in the performance parameters such as shadowless effect, color temperature, and color rendering index. There is also a focus on achieving uniform illumination. The arrival of LED technology in the medical industry has presented new opportunities for the development of OT lights. LED OT lights have gradually taken over the industry in recent years. They offer advantages such as excellent cooling, high-quality light, adjustable brightness, uniform illumination, no flickering, long lifespan, energy efficiency, and environmental friendliness.
What Are the Clinical Benefits of LED OT Lights?
We’ve already talked about the transition of OT lights from traditional incandescent lights to LED lights. Some of the benefits of LED are now readily stated: less heat, longer life, and more energy efficiency. However, these benefits are only the beginning. Only one of these frequently cited benefits, less heat, directly applies to surgical procedures if the point of new technology is to improve patient outcomes. LED lights emit significantly less heat compared to traditional incandescent bulbs, leading to increased comfort for surgeons and staff, which is particularly crucial during lengthy surgical procedures. Additionally, the colder light lessens the chance of exposed tissue drying up. Beyond just reducing heat, LED lighting has a number of additional clinical benefits.
Pure White Color
One of the remarkable characteristics of high-quality LED OT lights is the whiteness of the light they emit. Traditional halogen bulbs have a natural yellowish hue, typically around 3200 Kelvin (K) in color temperature. Manufacturers use pricey coatings and filters to block out some of the yellow light in order to counterbalance this yellow color, bringing the color temperature up to a more desired range of about 4400K. While these measures make the light appear whiter, the color is still not ideal. The application of coatings and filters is challenging, resulting in significant color variability between different halogen lights.
When multiple halogen lights are placed side by side in an operating room, the discerning eye can perceive differences in color and intensity among the light spots. These variations can be distracting for surgeons. In contrast, LEDs do not require filters or reflective coatings to “correct” the color because they can be precisely manufactured to provide white light at the preferred color temperature of 4400K. Additionally, as each LED lighthead contains several LEDs, any variances among the LEDs tend to cancel out one another, making the color match between LED lightheads considerably more stable than in halogen lights.
Improved Shadow Control
LED lightheads not only offer whiter and more consistent lighting but also provide superior shadow control compared to halogen lights. Typical components of traditional halogen systems are a single bulb and a multifunctional reflector. However, each facet of the reflector has a different shape and is located at a varying distance from the bulb. These variations may result in the formation of undesirable “hot” and “cold” spots within the light pattern, producing uneven illumination.
In contrast, an LED lighthead comprises multiple individual LEDs, with each LED contributing to the entire spot. These individual LED spots are precisely overlapped, ensuring that even if some LEDs are obstructed, the overall spot remains round and consistent. As obstructions, such as surgeons’ heads, move within the light field, the pattern remains unchanged.
The consistency of LED light eliminates distractions caused by shadows. In fact, some surgeons have even remarked that they no longer feel the need to use headlamps when using LED OT lights.
More Accurate Color Rendition
Another significant clinical benefit of LED lights is their superior color rendering capability. The Color Rendering Index (CRI) is commonly used to assess how well a light source allows observers to perceive subtle color differences. While most halogen lights have a high CRI, it primarily focuses on the visualization of pastel colors and may not accurately represent the rendering of deep, saturated red colors crucial in surgical procedures.
To address this, the lighting industry developed a specialized measurement called the R9, specifically designed to evaluate the rendering of deep red colors. While halogen lights may have CRI values in the mid 90s, their R9 values are typically in the low 70s. The reason for the significantly lower R9 values is related to the heat generated by halogen bulbs, primarily in the form of infrared(IR) light. As the human eye cannot detect IR light, its presence does not provide any clinical benefit. Manufacturers attempt to eliminate IR light from the surgical field using dichroic reflectors. However, in the process of filtering out the IR light, some of the desirable visible red light also gets filtered out, resulting in poor R9 color rendition.
LED technology eliminates the need for such filtering altogether. LEDs can be precisely designed to emit light only within the visible spectrum, without generating IR light in the first place. This eliminates the necessity to filter out IR light and preserves the integrity of the visible red light. Consequently, certain LED manufacturers have been able to increase their R9 values from the low 70s to the mid 90s. Surgeons will immediately notice the difference as red colors appear bolder and more vivid under LED lighting. This enhanced color rendition aids surgeons in quickly and accurately identifying tissues and making diagnoses, ultimately improving procedural efficiency and precision.
Clinical Justification Leads to LED Value
Currently, LED surgical lights come with a higher upfront cost compared to halogen lights. However, when justifying the increased purchase price, it’s important to consider the total cost of ownership, taking into account energy savings and reduced replacement bulb costs over time. While these financial factors are compelling, the primary argument for investing in LED technology lies in the clinical benefits it provides, which ultimately lead to improved patient outcomes.
If there are doubts regarding the value of LEDs, a practical approach is to arrange for a manufacturer to bring in an LED OT light on a mobile stand for a side-by-side comparison with a good halogen surgical light. In most cases, the comparison will be clear-cut, with even an untrained observer expressing a preference for LED lights.
Now, consider the significant impact this difference will have on a highly trained surgeon. The enhanced features and benefits offered by LED lights, such as superior color rendering, consistent illumination, reduced heat emission, and better shadow control, will greatly improve a surgeon’s experience and performance in the operating room, leading to better surgical outcomes and ultimately benefiting patients.
Mokolight-Your Wise Choice for LED OT Lights
Mokolight has committed itself to LED medical lighting for more than 16 years, with the aim of doing a great service to hospitals and healthcare facilities around the globe. For more information or queries about LED OT lights, visit our website or contact us!
