COLOR BLINDNESS an ethical analysis of and its implications in the workplace David C. Shishido Eyes, ears, nose, mouth and skin -- The two photoreceptors in the human eye, the building blocks of vision, are rods and cones. While rods are crucial mediators of vision in low light conditions and allow perception of black versus white, the focus of this paper will be on cones, which actively contribute to color vision. Cone photoreceptor activity is the foundation to what most humans consider “vision” --cones vastly outnumber rods in terms of usage in day- to-day activities of which the majority occur in room light-level conditions. In order to best understand the nature of human vision, I will briefly outline the process by which sensory perception is relayed from the eye to the brain. Within cones (and rods) there exist light-sensitive molecules, or cone pigments, (Rhodopsin in rods) which help transmit neural signals of color identification to the brain. Cone pigments, otherwise known as visual pigments, are made of two components. The Vision “begins” when photons of light, reflected on objects, are absorbed by the eye. The 11-cis¬¬-retinal undergoes conformational change in reaction to absorption of these light-waves, activating the opsin proteins to trigger changes within the photoreceptor that relates the neural signals to the brain. Our understanding of opsin is the key component to color blindness because it is here where the root of color blindness begins. The opsin genes of red and green, the most commonly unrecognizable colors, are not only located adjacent to one another, but are also 98% identical. Research suggests that the similarities between red and green opsin genes caused homologous recombination throughout human evolution (Neitz, 2009). Most importantly, these recombinations have led to excess creation of red and green pigment genes, which ultimately lead to color blindness via the X chromosome. These genes can either be missing, damaged or in excess and because males have only one X chromosome, males are more likely than females to experience color blindness (functional genes on one of the two X chromosome in females is capable of providing the gene pigments necessary for color detection). G ender is only one of two disparities in the prevalence of color vision deficiency -- there is equally, if not greater, inequalities in terms of affected race. Color deficiency is most common in European males (at an 8.1% high, almost twice that of other groups such as Asian-American males at a 5.9% high) followed by Asian, African American and finally Native America males (Delpero 2005). Unsurprisingly, less than 1% of women are affected across all genders. While there B erkeley S cientific J ournal • C olors • F all 2012 • V olume 17 • I ssue 1 • 1 B S J the channels of sensory perception in the human body are vast and complex. Vision allows us to perceive shapes and understand the world around us. When stopping at a traffic light at night unable to identify the relative position of lights, red and green distinguishes whether to stop or go. Green versus ripe tomatoes and rare versus well-done steak prove difficult to distinguish in the kitchen. A day at the beach might result in overexposure to the sun without the necessary warning signs of bright red skin. These are just a few of the problems that color vision deficient individuals face in daily activities. Color identification is undoubtedly a crucial component in our perception of the world, and yet there are a vast amount of individuals who live with color identification deficiencies ranging from red and green to blue and yellow. In this paper I will offer an introduction of the origins of color blindness, provide insight as to the groups of individuals most impacted in terms of lifestyle and employment by its limitations, and discuss current and future technology available to compensate and hopefully cure color vision deficiency. first is a protein known as opsin, while the second is a chromophore known as 11-cis-retinal. While visual pigments share the same chromophore, the opsins are of greatest concern in this article because opsins vary across different types of cones. These play major roles in the determination of which colors the brain perceives.
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Open Access
Jan 1, 2018
Sushil K + 2
