From Lawrence Brown
Sheffield
The chemists at BASF in Germany haven’t really thought it through. Their
electric blue-tinted windscreen
(8 December, p 21)
will reduce the driver’s
ability to see red traffic lights and brake lights, by inducing a similar colour
vision defect to that known as protanopia, which is caused by a lack of
long-wave sensitive cone cells in the retina. Further, there are very few
short-wave sensitive cones in the human fovea, so visual acuity in the blue part
of the spectrum is very poor.
Blue is the most dangerous colour to tint vehicle windscreens or even
driver’s sunglasses. If a filter is required, it should be colour neutral for
safety reasons.
