Tryptophan Excited States and Cataracts in the Human Lens

Abstract

WE present here a study of the fluorescence and phosphorescence of human eye lenses in vitro with regard to the mechanisms of formation of cataracts. Light transmission by the cornea decreases rapidly with decreasing wavelength, and is essentially zero for wavelengths less than 293 nm^1–3. The important effect of this corneal absorption was demonstrated by Bachem³ who induced cataracts in guinea-pigs and rabbits with ultraviolet light and presented an action spectrum to show that the efficiency of in vivo cataract production rose steeply, from zero at 293 nm to maximum at 300 nm, and then fell off sharply at 313 nm with a long tail extending to about 365 nm. This action spectrum and the corneal absorption spectrum are shown in Fig. 1.