D-15 performance with short wavelength absorbing filters in normals

Short wavelength absorbing filters (SWAF's) have become very popular in the prescription and commercial sunglass markets. Like other chromatic filters SWAF's have the potential to alter color vision. Performance on the Farnsworth Panel D-15 (D-15) test was measured to determine whether any of 4 popular SWAF's, in the form of sunglasses, produced color vision changes in 22 color normal adults. Using standard illuminant C, observers were tested under the following conditions: wearing no filter, a 1.0 log unit neutral density filter (NDF), or one of the following SWAF's: Corning CPF 550; NolR Amber 40%; Blu Blocker; and Vuarnet 4006. In addition, the Vuarnets were tested outdoors in shaded daylight to determine the effects of increased illumination. The NDF served as the control and had no effect on D-15 performance. Compared to it, only the Blu Blockers and Vuarnets affected D-15 cap arrangements for these SWAF's significantly. Blu Blocker error patterns had no predominant axis, whereas the predominant axis of errors in both Vuarnet conditions was tritan. Results of quantitative analysis performed on three factors confirmed these findings and indicated the Blu Blockers and Vuarnet SWAF's caused moderate and moderate-to-severe levels of color confusion, respectively. Increasing the illumination level improved performance with the Vuarnets, but it remained significantly outside the normal range.