Loading... Please wait...

Categories

Exam Lights

Examination lights are used in medical facilities across the world for local illumination of the patient’s body during diagnostic procedures and minor procedures. Examination lights are not to be confused with surgical lights that are intended for use in operating theaters.

Background

Careful examination of the skin and sclerae requires reliable lighting equipment that does not produce glare, shadows or other impeding effects. Examination rooms should feature lighting systems that provide a combination of comfortable ambient and task lighting.Poor lighting may hamper the performance of the medical team, lengthen the procedure, and even cause errors. And so can lighting that is too bright.

The diversity of lighting devices available on the market, the variations in technical and design specifications make the selection of the right equipment a truly formidable task. Although the manufacturers provide detailed information about technical specifications of the device, an adequate interpretation of the data by clinicians and other staff involved in the selection process is often difficult.

This guide aims to educate the potential buyer about some of the most important characteristics of the examination lamps in order to facilitate the selection.

History

Until the advent of the light bulb in the late 19th century, hospitals relied mostly on the natural light. Operating rooms were planned with windows facing the southeast, and many also featured windows in the ceiling. The major issues back then were limited hours of daylight and heavy dependence on weather conditions. In addition, beams of light that reached the operating theatre could be easily blocked by people or objects, and placing mirrors at the corners of the ceiling to redirect light towards the patient barely solved the problem.

Electric light technology entered medical facilities for the first time in the 1880s and has been evolving continuously ever since. Today, incandescent and fluorescent lamps that have prevailed in the examination rooms for the past decades are being gradually supplanted by the more advanced light-emitting diode (LED) technology.

Types of Examination Lights by Mounting Configuration

  • Ceiling-mounted
  • Wall-mounted
  • On floor stand

Frequently, the lamps can be assembled in any of the three configurations.

Lighting Specifications

Performance requirements for the lighting devices intended for use in examination rooms are defined by a number of international bodies, including the International Electrotechnical Commission (IEC). Some of the key technical characteristics to look at are illuminance, color rendering index, and color temperature.

Illuminance (min. 1000 lux)

Illuminance is the total quantity of light falling on the surface, per square meter. Illuminance (E) is measured in lux.

E (lux) = luminous flux (lm) / area (m2)

Requirements for light levels vary across different parts of the hospital; even a single room may require different lighting in different sections. For instance, 500 lux is sufficient for the general lighting in the examination room, but the minimum requirement for examination lamps is 1000 lux.1

Color Rendering Index (min. 85)

Skin color can tell a lot about the patient’s condition, but color judgment is heavily influenced by the spectral composition of light. Skin examination is best performed under bright sunlight.2 The colour rendering index (CRI) indicates how closely the light from the examination lamp reproduces sunlight, which is assigned a reference value of 100. In general, CRI greater than 80 indicates ‘good’ color rendering, greater than 90 – ‘very good’.

For the examination lights, the document Particular requirements for the basic safety and essential performance of surgical luminaires and luminaires for diagnosis, 2009 issued by the International Electrotechnical Commission (IEC) establishes the minimum CRI at 85.3Most modern devices, however, will have a CRI >90.

Color Temperature (3,000 – 6,700 K)

Color temperature (Tc) characterizes the color of the light spectrum emitted by a lamp. Color temperature is measured in Kelvins (K). For instance, warm white light will have a color temperature of <3,300 K, neutral white - 3,300 – 5,300 K, and daylight white - >5,300 K. The recommended range for the diagnostic lights according to the IEC is 3,000 – 6,700 K.3 Lamps that allow adjusting the color temperature and light intensity are usable in a wider range of clinical scenarios and enable the medical staff to be more functional.

Lamp Technology

There are three main types of lights used in medical facilities:

  1. Incandescent lamps
  2. Fluorescent lamps
  3. Light emitting diodes (LED)

Conventional incandescent lamps are commonly seen in homes. They usually have a very good color rendering index, but short service life. Incandescent lamps are the least energy-efficient electric light source with low luminous efficiency. Luminous efficiency characterizes how much light a lamp emits per unit of consumed electrical power. It is measured in lumens per watt (lm/W).

LEDs, on the other hand, are the most durable and energy-efficient. Although they typically come with a higher price tag, the investment usually proves to be worthwhile within a couple of years due to significant energy savings.

Fluorescent lamps fall somewhere in the middle between LEDs and incandescent lamps in terms of lifetime and luminous efficiency. They are more expensive than incandescent lamps, but usually cheaper than LEDs.

The characteristics of the three main types of lamp technology are summarized in the Tab. 1.

Tab. 1. Characteristics of the three main types of lamps used in examination lights

 

Incandescent

Fluorescent

LED

Initial cost

Low

Moderate

High

Luminous efficiency (lm/W)4

12

80

150

Lifetime (hours)

1,000

10,000

30,000

References

  1. 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.
  2. Morgan-Hughes, J. (1968). Lighting and Cyanosis. British Journal of Anaesthesia, 40(7), pp.503-507.
  3. IEC Subcommittee 62D, Electromedical Equipment. IEC 60601-2-41 Edition 2.0, Medical Electrical Equipment, Part 2-41: Particular Requirements for the Safety of Surgical Luminaires and Luminaires for Diagnosis. International Electrotechnical Commission, Geneva, Switzerland. August 2009.
  4. Balzani, V., Bergamini, G. and Ceroni, P. (2015). Light: A Very Peculiar Reactant and Product. Angewandte Chemie International Edition, 54(39), pp.11320-11337.
Sort by:

Pages :

Pages :

 

Customer Service

CONTACT INFO

USA Pharmacia Sp Z.O.O

Ziebicka 40,
Wroclaw, Poland
Phone : +48 (797) 197805 sales@uspharmaciaspzoo.com