The human lens is light brown to orange in middle age. The absorption spectrum of the lens provides a physiological adaptation to the increased vulnerability of the older retina. An IOL without adjusted absorption might cause problems of visual discomfort and retinal damage.

The Orange UV absorber works as a light filter and so resembles the normal human lens at middle age.

Yellow IOLs have been on the market for some time now. The absorption characteristic of the yellow lens is less physiological, however. Filtering out purple and blue results in decreased sight in the dusk. A yellow filter is inferior to a physiological light filter during the day as well. Skiers know this because the modern brown-orange ski goggles are usually more effective than the earlier yellow ski goggles. Model 440 with orange UV absorber is not only theoretically better, but it will also result in a better customer satisfaction.