LONG-WAVELENGTH PASS FILTERS DESIGNED FOR THE MANAGEMENT OF COLOR-VISION DEFICIENCIES

This study reports on the effectiveness of long wavelength pass filter s dispensed as tinted spectacles as an aid for individuals with congen ital red-green color vision deficiencies, The effectiveness of the fil ters was evaluated by the performance on a series of clinical color vi sion tests and a questionnaire after the subjects had tried the lenses for 1 week, The lenses improved performance on color vision tests tha t required discrimination between large color differences, particularl y between red and green hues, However, performance was degraded on tes ts which required fine color discrimination or used colors that were l ocated parallel to the tritan confusion axis, The improved performance on certain tests was primarily based on brightness artifacts induced by the filters, whereas the degraded performance on the other tests wa s due to the absorption of short- to midwavelength light hy the filter s, A slight majority (56%) of the subjects rated the filters as being moderate to highly effective in improving their color discrimination, Nevertheless, only 17% were interested in actually purchasing a pair, Common reasons for rejecting the filters were the color distortions pr oduced by the red filters and fewer colors were actually perceived whe n wearing the filters.