http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001997/ 1 in 10 men NIH, 2011 National Center for Biotechnology Information National Library of Medicine 1 in 10 men common symptom of colorblindness colorblindness National Center for Biotechnology Information National Library of Medicine 1 in 10 men National Center for Biotechnology Information affecting approximately one in 10 men National Institutes of Health common symptom of colorblindness National Center for Biotechnology Information National Center for Biotechnology Information 1 in 10 men estimated color vision deficiency estimated National Library of Medicine National Center for Biotechnology Information National Library of Medicine National Center for Biotechnology Information colorblindness National Institutes of Health National Library of Medicine National Center for Biotechnology Information National Library of Medicine color blindness National Library of Medicine U.S. National Library of Medicine