Influence of lens autofluorescence on retinal nerve fiber layer evaluation

BACKGROUND: 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. PATIENTS AND METHODS: 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. RESULTS AND CONCLUSION: 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.