It may also be that after surgery he was able to see certain ultraviolet wavelengths of light that are normally excluded by the lens of the eye; this may have had an effect on the colours he perceived.
Det kan också vara så att han efter operationerna kunde se vissa ultravioletta våglängder av ljus som normalt sett exkluderas av ögats lins; detta kan ha haft en effekt på de färgtoner han uppfattade.