December 7, 2017

The human eye is sometimes compared to a camera. I’ll grant this is true if someone can find me a camera that is


1.      Auto-adjusting to light from near-total darkness to bright sun with no intervention


2.      Self-cleaning, self-nourishing, self-regulating, and often self-repairing


3.      Auto-stabilizing even though its mounted on a “tripod” that walks, runs, lies down, tilts, turns, rotates with no warning (and never degrades an image)


4.      Seamlessly integrated with a second camera that sits about 2.5 inches away.


5.      Seamlessly integrated into the universe’s most advanced neural network that can make decisions, voluntary movements, laugh or cry based upon the images captured


The human visual system is so exquisite we might not realize there are things we can do to help our eyes function optimally. For example, we can pay attention to contrast in our workplace.


While the eye functions well across most any conditions, it doesn’t work equally well in them all.


What did you just do? Did you squint? Did your reading rate slow down? Did you move closer to the computer? Did your eyes miss a step so you had to re-read a word? Now read those sentences three times through. Are your eyes burning yet? Headache at all? What if you were an iron worker on a rooftop and not sitting here at your desk? The consequences of hesitating or seeing imperfectly can be profound.


Contrast is the difference in how dark an object is compared to its background. Black on white is 100% contrast. Last week, we talked about reading the chart and how eye doctors make it easy on the visual system with black letters on a white background, but contrast isn’t only about reading. Consider these examples:


1.      What color is the trim in your office compared to the wall color? Sharply contrasting trim color is a peripheral visual cue to a person’s environment and can aid in navigating a space. (Even if people don’t consciously notice).


2.      What is the level of illumination in various parts of the work environment? Large differences in illumination reduce contrast. What about the loading dock versus inside the warehouse?


3.      Does the work environment contain a lot of matte surfaces with low reflection or glossy surfaces that reflect a lot of light? Reflections reduce contrast.


4.      Look for objects that blend into the background.


5.      What color are any stairs in the office? The handrail?


6.      Do you use pencils at work (lower contrast) or ink pens (higher contrast)? Low contrast print increases eye fatigue exponentially


7.      When did you last review the contrast settings on your photocopier or computer monitors?


8.      Take note of moving objects and try to optimize contrast between moving parts or objects and stationary ones.


Improving contrast can be a great benefit for visual efficiency and safety in the workplace. You see better in high contrast than you do in low contrast. You read more efficiently, navigate your environment more surely, make decisions and react more quickly, and you are less prone to injury when you see better. Remember, your visual system is mapping and tracking objects in your peripheral vision even if you aren’t noticing them directly! Your peripheral vision adores high contrast.


My father was an electrician, and his his hands were severely burned at work. Someone from a floor above him used a “fish steel,” a long steel-colored tool for pulling wire, and this tool came down through the ceiling and caused an arc in the panel where my father was working. I sometimes wonder what might be different if that tool had been bright pink rather than the color of wire. Would he have seen it in his peripheral vision a split-second sooner?


Next week, I’d like to talk about glare and its effects on visual performance. Until then, you know where to find me.


Dr. Mark Kahrhoff

Complete Safety, LLC



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