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Julie Lovell, Jeff C Rabin; Perceptual Learning of Hue Discrimination in Jewelry Appraisers. Invest. Ophthalmol. Vis. Sci. 2021;62(8):2807.
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© ARVO (1962-2015); The Authors (2016-present)
Perceptual learning can improve visual acuity, contrast sensitivity, vernier acuity and stereo-acuity in adult amblyopes beyond the critical period for visual development. Latent neural connections and/or development of new connections may underlie these improvements, coupled with the relative balance of excitatory and inhibitory neurotransmitters. Recently we reported superior hue discrimination in largely elderly jewelry appraisers who must discriminate subtle changes in hue to ensure optimal gemstone valuation. We report that the basis for this enhancement depends on M and S cones.
Jewelry appraisers (n=18, mean 57 ± 12 YO) undergoing color vision certification on the FM 100 hue test in accord with the National Association of Jewelry Appraisers (NAJA) were invited to participate in a study to assess performance on the Ishihara (to rule out hereditary color deficiency), FM-100 Hue (currently used by NAJA), desaturated D15 and the cone contrast test (Innova Systems, Inc) which quantifies L, M and S cone contrast sensitivity (CS). Subjects provided written informed consent for our IRB approved protocol.
All subjects passed the Ishihara and desaturated D15 tests confirming normal color vision. Combined M and S cone CCT scores were predictive of FM 100 Hue total error score (TES; F = 7.76, P < .02, r2 = .45). 17 of 18 subjects had 100 Hue TES scores which were >2SD below age-matched normal means indicating enhanced hue performance. Partial TES analysis revealed error rates were greatest on the blue-yellow (BY) axis.
Elderly jewelry appraisers show enhanced hue discrimination due to a highly practiced, reward-based repetition—tenets of perceptual learning. Correlation between M and S CCT and FM Hue scores suggests greater importance of M and S cone hue discrimination and CS for accurate gemstone discrimination. This is evident in Fig. 1 which shows perception of a highly valued gemstone (https://www.thepearlsource.com/blog/most-valuable-gemstones/) in normal, protan, deutan and tritan views (https://www.color-blindness.com/coblis-color-blindness-simulator/). The protan (lacks L cones) and normal views essentially match while deutan (lack M cones) and tritan (lack S) views appear different from the normal, highly valued view, exemplifying M and S cone importance in gemstone hue discrimination.
This is a 2021 ARVO Annual Meeting abstract.
Figure 1. Perception of a highly valued gemstone innormal, protan, deutan and tritan views.
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