Fig 4. Polar plot showing differences in visual search performance index (‘high’ saturation–‘original’ condition) for all the colour combinations for both protans (red-dashed lines) and deutans (blue solid lines).

The negative numbers in the polar plot refer to worsening effect and the positive numbers indicate a positive or improvement. On increasing the saturation of the display, improved visual search performance index for most combinations was noted for protans than deutans. The grey zone (mid central rings) is considered a region of “no change”, as the change in visual search performance index is ≤ 10%.