Visual Significance of Yellow Optical Filters

Abstract

In this study, optical lenses were formulated to remove wavelengths shorter than 450 nm from various environmental light sources. They were tested for their ability to improve vision by preventing harmful and useless light from entering the eye, and to transmit nearly ail visually useful wavelengths. A spectral colorimeter was used to determine the alterations of the transmission of mixed wavelengths of light caused by these yellow lenses. Further studies of how these lenses effect contrast vision in elderly and partially visually impaired human eyes were done.

The results have shown that the yellow lenses adjusted the wavelengths of light reaching the spectral colorimeter from various environmental light sources. They removed short wavelength light (<450 nm), but also transmitted from 500 to 600 nm very efficiently. Studies of contrast vision in elderly subjects and those with early cataracts (primarily) suggested that the yellow lenses improved contrast vision appreciably.

The findings show that an optical filter that can prevent short wavelength light from entering the eyes of elderly and visually compromised people has a positive influence on their vision.