Enhancing illumination

March 1, 2010
Seeing what you're supposed to see

Seeing what you're supposed to see

by Anne Nugent Guignon, RDH, MPH
[email protected]

The dental treatment room is full of challenges that affect or limit visual acuity, which results in less than optimal clinical performance, compromised treatment outcomes, and operator fatigue and frustration.1 Improving visual acuity through enhanced illumination techniques is the answer.

Only a few articles have been published through the years that discuss illumination in the dental treatment room,1–3 so I turned to textbooks to find information about improving visual acuity in the general workplace. Over the holidays I ordered Martin Helander's textbook, “A Guide to Human Factors and Ergonomics.”4 While well written, this book is not casual, escape–from–the–real–world reading.

Textbook writing is typically dry and sparse, built around a logical presentation of the facts. New textbooks often contain case studies to help students transfer theoretical principles into actual practical applications. Despite the fact that Helander's book presents basic ergonomic principles, several chapters contain fundamental and practical gems that directly relate to illumination in the clinical dental environment.

Ergonomists recommend point source lighting for close inspection work. These experts in workplace safety propose that visual tasks involving work with small objects require more illumination. In addition, tasks that entail highly difficult inspection require an even greater volume of light. Due to natural physiological changes in the eye, lighting requirements increase as workers age.4 Ergonomists also understand that inadequate or inappropriate lighting and glare not only increase eye fatigue, but also have a negative impact on overall worker fatigue.4–5

This discussion of how lighting affects work makes it clear how proper illumination is critical in the dental treatment room. For the most part we work with 32 teeth, a set of gums, and surrounding supporting structures, and our work involves demanding inspection and evaluation. The case studies in the book demonstrate how proper point surface lighting reduces errors when workers use appropriate enhanced lighting systems.

There is also a discussion about the difference between illumination and luminescence and how these different types of lighting work synergistically to enhance visual acuity. Illumination refers to light that falls on a surface, while luminescence is light reflected from a surface.4 Overhead lights, headlights, lighted mirrors, and lights on a handpiece all create illumination. Light reflected off a ceiling or walls, a mouth mirror, or an oil–coated moisture barrier are examples of luminescent light sources.

Visual acuity is also affected by the type, color, amount, and intensity of light.1–6 Reflected room light can be soothing but does not necessarily enhance clinical visualization. For example, an outdoor sodium vapor lamp can illuminate an area, but the color and quality of that type of light makes it very difficult to distinguish colors and small details, so it is not an appropriate choice for indoor lighting.4 Light that is too bright creates glare and therefore is another poor choice.4–5 Dust, scratches, fog, moisture beads, and water spray also affect the quality and volume of light. As we age, the lens in our eye becomes more cloudy and rigid, which results in an increased need for brighter light sources and a corresponding reading correction.4–6

A wide variety of solutions are available that enhance visual acuity in the clinical setting, ranging from cleaning the overhead light lens cover to using an auxiliary headlight attached to a pair of magnification loupes.

Let's start with options that don't cost a dime and take only minutes to implement. First, clean the dust and smudges off your overhead light with a soft cloth and nonabrasive cleaner to avoid unnecessary scratches. Periodically wipe mouth mirror surfaces with mouthwash–dampened gauze to reduce fogging and prevent water droplets from beading on the surface. Warming the mouth mirror in warm water eliminates fogging. Mirrors used in intraoral photography remain clear when warmed on a heating pad covered by a soft towel.

Replace worn out, scratched overhead light covers, face shields, and mouth mirrors. The autoclavable Mirror Gear mirror covers help prevent scratches, which extends the mirror life over time. Consider upgrading to Zirc's Crystal Mirror, which is made with a special surface that reflects more light than rhodium and produces more accurate color rendition. Double–sided or lighted mirrors and Orascoptic's DK fiber–optic periodontal probe also improve visualization.

Point source lighting is available through lighted high–speed handpieces, ultrasonic handpieces, or inserts and specialty devices such as the Isolite. Auxiliary headlights, typically attached to magnification loupes, provide hands–free illumination coupled with a magnified image. Lightweight, portable, cordless LED systems are becoming increasingly popular, especially as the quality of light improves. Lighting experts report the quality and output of LED lighting doubles every six to 12 months, a technological pace equivalent to today's smart phones.

Ergonomists focus on ways to prevent needless workplace–related injuries and reduce the physical stress created by a less than ideal workspace. Research and development in the manufacturing world are also showing increased interest in safety. Consider improving your professional comfort zone by adding or upgrading illumination. It's never too late to see the world in a new light.


  1. Kobayashi H, Sato M. Physiological responses to illuminance and color temperature of lighting. Ann Physiol Anthropol. 1992 Jan;11(1):45–9.
  2. Preston JD, Ward LC, Bobrick M. Light and lighting in the dental office. Dent Clin North Am. 1978 Jul;22(3):431–51.
  3. Viohl J. Dental operating lights and illumination of the dental surgery. Int Dent J. 1979 Jun;29(2):148–63.
  4. Helander M. A guide to human factors and ergonomics – 2nd ed. Boca Raton: Taylor & Francis, 2006.
  5. Lampi E. The sources of light and lighting at work. Acta Ophthalmol Suppl. 1984;161:66–83.
  6. Werner JS, Peterzell DH, Scheetz AJ. Light, vision, and aging. Optom Vis Sci. 1990 Mar;67(3):214–29.

Anne Nugent Guignon, RDH, MPH, is the senior consulting editor for RDH magazine. She is an international speaker who has published numerous articles and authored several textbook chapters. Her popular programs include ergonomics, patient comfort, burnout, and advanced diagnostics and therapeutics. Recipient of the 2004 Mentor of the Year Award, Anne is an ADHA member and has practiced clinical dental hygiene in Houston since 1971.