[In vivo autofluorescence. Measurements of human crystalline lenses with cataract and normal findings after excitation with monochromatic light].

In 25 eyes with nuclear cataract, 18 eyes with posterior subcapsular cataract, 25 eyes with cortical cataract, and 23 eyes without any pathological lens changes, the maximal fluorescence intensity was determined after excitation with monochromatic light at 365 nm, 405 nm, 436 nm, and 485 nm. The coefficient of variation was smaller than 5%. All eyes with cataract underwent cataract surgery a few days after the fluorescence measurements. The fluorescence spectrometer, especially constructed for in vivo measurements, consists of a modified slit lamp (Zeiss 75 SL) and an optical multichannel analyser (OMA) for gauging the data. The clinical trial was undertaken to determine whether, considering the influence of age, there is a difference between the fluorescence intensities in eyes with the above named cataracts and noncataractous eyes. The data were analyzed to determine the effect of age upon fluorescence intensity for all excitation wavelengths in both cataractous and noncataractous eyes. Age had an influence on the fluorescence intensities for all four excitation wavelengths. Assuming that the influence of age was not dependent on the state of the lens, it was quantified for all measurements and an "age-corrected" fluorescence intensity was calculated. The statistical analyses of these "age-corrected" fluorescence intensities revealed a significant difference (P < 0.001) for all of the types of cataracts examined and for normal eyes. The cataract types examined and the normal eyes showed differences in their fluorescence feature. To assess the fluorescence intensities obtained after excitation with the wavelengths mentioned above, one must take into consideration the influence of age on the measurements.