The effect of a short-wave filtering contact lens on color appearance

Objective: We assessed the effect of a contact lens that filters short-wavelength (SW) visible light on color appearance. These effects were modeled and measured by direct comparison to a clear contact lens. Methods: 61 subjects were enrolled, and 58 completed as cohort; 31 were 18-39 yrs of age(mean = 29.6 ± 5.6), 27 were 40-65 yrs of age (mean = 50.1 ± 8.1). A double-masked contralateral design was used; participants randomly wore a SW-filtering contact lens on one eye and a clear control lens on the other eye. Subjects then mixed three primaries (including a short-wave primary, strongly within the absorbance of the test lens) until a perceived perfect neutral white was achieved with each eye. Color appearance was quantified using chromaticity coordinates measured with a spectral radiometer within a custom-built tricolorimeter. Color vision in natural scenes was simulated using hyperspectral images and cone fundamentals based on a standard observer. Results: Overall, the chromaticity coordinates of matches set using the SW-filtering contact lens (n=58; x=0.345, y=0.325, u'=0.222, v'=0.470) and clear contact lens (n=58; x=0.344, y=0.325, u'=0.223, v'=0.471) were not significantly different, regardless of age group. Simulations indicated that, for natural scenes, the SW-filtering contact lens that was evaluated changes L/(L+M) and S/(L+M) chromatic contrast by no more than -1.4 to +1.1% and -36.9% to +5.0%, respectively. Conclusions: Tricolorimetry was used to measure color appearance in subjects wearing a SW-filtering lens in one eye and a clear lens in the other. Results indicate that imparting a subtle tint to a contact lens, as in the SW-filtering lens that was evaluated, does not alter color appearance for younger or older subjects. A model of color vision predicted little effect of the lens on chromatic contrast for natural scenes.