[MCOH-EH] vision testing

[Swift, Melanie]

Maribeth, some background to know:

1. Color vision deficiency (CVD) is not one consistent thing. People can have all kinds of missing or malfunctioning cones, resulting in different effects on the perceived color spectrum. It is more common to have a type that affects the red or green cones (protan or deutan defects) but people can also have problems primarily with the blue cones (tritan defects) commonly called "blue-yellow" deficiency.
2. CVD can be inherited, but it can also be acquired, especially with other ocular conditions like glaucoma or diabetic retinopathy.
3. CVD may be a disability protected under the ADA.
4. CVD may be a genetic disorder protected under GINA.
5. People with CVD often have the ability to compensate.
6. Lighting can have a huge impact on someone's ability to perceive color, so you can test someone in a room with the standard lighting required medically, but if in the "real world" they have less illumination you will not detect their problem.
7. Most available tests of color vision do not detect tritan defects - and a lot of medical point of care tests are in the blue-yellow spectrum.

Therefore, color vision testing is a medical test, to identify a medical problem that may be a genetic problem. You can readily appreciate the ADA and GINA hazards here. Someone can fail the medical test but still be able to discern what they need to, and correctly interpret a color-based test, usually by matching the sample against the control. Also someone can pass a color vision test, but still not be able to distinguish blue from olive, or still not be able to correctly perform a POCT.

For POCTs relying on color detection, we use annual competency tests, in which the person must demonstrate they can do the test properly and interpret the results correctly. Whether they are seeing ochre where you see lemon is really unimportant, as long as they match their ochre to the right interpretation. Competency tests are not a medical test!

If you have a color based flag system in which the flags are the same size, shape and location and the only difference is the color, look for an alternative. Over 5% of the male population has inherited (Hello Gina!) red-green CVD. Simply having a symbol, letter, or word over the flag, or instead of the color flag, would make it work for everyone. Or you could have any alert light up only to indicate a problem, whereas normal could have a clear background.

Same goes for presentation slides, heat maps, and other things for public consumption - if you are relying on everyone in the audience to distinguish red from green you are going to be handicapping a significant number of your audience.


Melanie Swift, MD
Director, Vanderbilt Occupational Health Clinic
http://occupationalhealth.vanderbilt.edu


-----Original Message-----
From: MCOH-EH [mailto:mcoh-eh-bounces at mylist.net] On Behalf Of Jenkins, Maribeth
Sent: Wednesday, May 18, 2016 9:19 AM
To: mcoh-eh at mylist.net
Subject: [MCOH-EH] vision testing

Good morning group- We have traditionally only vision/color blind tested our employees working with lasers.  More questions are arising in my organization, that I hope you can help me answer. 

	Do you conduct color blind/vision testing ?  

	If yes, what populations are tested?

	What testing tools do you use? 

	How often are they tested?

	Our house wide computerized charting has red and green flag alerts, any thoughts on color blind testing all populations using EMRs? 

Thanks, 

Maribeth Jenkins, MSN, RN, LMT, CWC
Employee Wellness Manager
Hendrick Medical Center
1900 Pine Street
Abilene, TX 79601
Phone: (325) 670-3010 
Fax: (325) 670-3051
mjenkins at hendrickhealth.org
www.ehendrick.org


            








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