The Role of Tinted Lenses in the Perception of Color Deficiency

Purpose: Many different approaches have been used to improve the color perception in patients with color deficiency. Currently, filters and tinted contact lenses are the most widely-available method to enhance color perception. Filters have been shown to help patients to pass pseudoisochromatic color tests, to better perform their daily activities, and enable them to better enjoy nature and art as well. The aim of this study was to evaluate the efficacy of monocular Neuchroma tinted lenses in improving the color perception for those with color vision deficiency. The specific combination of tints was selected to mimic the neutral (black) point for protans and deutans to optimize contrast. These were compared to neutral density filters as a control condition, and a red filter as the established compensatory treatment for red-green color deficiency. Methods: 12 subjects (three females and nine males) with red-green defect, aged 14-88 years, were involved in this study. Subjects were asked first to perform Farnsworth-Munsell 100 hue wearing no tint. Then, participants then performed the digitial ColorDx test four times, with different filters. We used R3+RW3+RD3, IR3, neutral density and red filters in front of the right eye for protans, and IR3+RW3+RD3, LV2+LV3, neutral density and red filters for deutans. Each filter was put inside a black mask to make their appearance appear as similar as possible. After that, participants performed Farnsworth-Munsell 100-hue test for a second time with filter that caused minimal errors on ColorDx test placed in front of their right eye. Results: We found no statistical difference between neutral density and NeuChroma lens IR3 for protans, (p= 1.000). VL2+VL3 did not give a different result than ND (p= 0.339) for deutans. There was no statistical different between neutral density lens and IR3+RD3+RW3 NeuChroma lenses on ColorDx for all subjects, (p= 0.694). There was a remarkable reduction in total error scores on ColorDx test with the red filter (p = 0.003). Total error score on FM 100-hue test significantly increased with the red filter (p = 0.009). Conclusion: The results showed that tinted lenses has no significant impact on color vision defect subjects. The red filter improved color vision performance in three deutan subjects and shifted the defect from mild protan to mild deutan in one subject