There is also the issue of the sensitivity of the human eye:
The sensitivity of the human eye to light of a certain intensity varies strongly over wavelengths between 380 nm and 800 nm. Under daylight conditions, the average normal sighted human eye is most sensitive at a wavelength of 555 nm, resulting in the fact that green light at this wavelength produces the impression of highest “brightness” when compared to light at other wavelengths.
The white light of LEDs is made up of three precise separate frequencies of
Red LED - 633nm
Blue LED - 490nm
Green LED - 560nm
So it is easier to tune a white LEd to match the sensitivity of the eye without 'wasting' energy by emitting light at frequencies the eye isn't sensitive to.
Good points there. Recently my work place had all their tubes replaced with LED's, sure the whole place were brighter but many workers said that it actually hurt their eyes after a while. I did feel that myself for a couple of weeks but now I don't notice it thankfully. Don't know what type/output these ones are, I like 'cold white' option in my torches, they are certainly similar to that.