Lens autofluorescence scan. Lens autofluorescence of a 28 year old subject (A) and a 61 year old subject (B). The fluorescence intensity is given as ng/ml. The x-axis represents a visual axis in mm. Ppost is a peak fluorescence of the lens posterior pole, and Pant is a peak fluorescence of the lens anterior pole. In the older subject values of the peaks appear higher and the difference between posterior and anterior peaks is greater than that of the young subject. Due to the accumulation of denaturated lens proteins in the advanced age lens, light absorption increases, and the back emitted fluorescent light from the posterior peak appears less intense than the light from the anterior peak.