Influence of lens autofluorescence on retinal nerve fiber layer evaluation

Yellow-brown coloration of the human lens increases with age and is associated with increasing lens autofluorescence. This may interfere with retinal image through scatter and absorption.

We measured the lens autofluorescence (AF) of 30 eyes of 30 healthy subjects and evaluated their retinal nerve fiber layer (RNFL) visibility from fundus photographs. These otherwise healthy eyes showed a varying degree of yellow-brown coloration of the lens. Lens fluorometry was carried out with a previously described technique using blue-green AF range (495 nm/520 nm). RNFL photographs were taken with a Canon CF-60 ZA wide angle camera with blue (495 nm) interference filter and low-sensitivity, high resolution black-and-white film.

Lens yellowing expressed here by means of lens autofluorescence measurements, was statistically significantly (r = -0.53, p = 0.0008) correlated with the RNFL visibility score. In stepwise regression analysis adding age to the model including only the maximum AF did not reduce the residual standard deviation statistically significantly (p = 0.1). This suggests that lens yellowing has an effect on RNFL visibility and may be an important confounding factor in clinical RNFL evaluation.