It has been known through published research that small amounts of optical defocus, such as those experienced when looking through the intermediate corridor of progressive lens can cause such colour-misconceptions.
In a transport environment there are serious safety implications to the potential misjudging signal colour.
A 2016 derailment in Western Australia involved reports from the train driver that observing the points enhancer viewed through his tinted prescription glasses it appeared yellow, but when the glasses were taken off the point enhancer appeared red.
Whilst there were many other factors to the derailment it was concluded that the prescription glasses may have further contributed.
An experimental evaluation will be conducted to examine whether prescription spectacles with progressive lenses might alter the perception of signal colours and also whether selected spectacle lens tints might also have an effect on signal colour perception.
Data collection will include site visits and specialised laboratory-based testing and the research will aim to provide recommendations on how to mitigate the risk of colour misconceptions caused by prescription lenses.