Abstract
Abstract: :
Purpose: Lens autofluorescence is of relevance to visual function of the individual. First of all, the fluorescent light itself emitted by the lens also stimulates the retina. This is visible as a veil that may hinder observation of weakly illuminated objects (UV headlights). Apart from that, the autofluorescence is indicative for light losses in the lens and light scattering. Methods: Psychophysical effects of UV light are compared to the potential source of autofluorescent light in the human eye lens. Isolated lenses were used, normal and with cataracts, from donors aged 21 to 86 years. Light emitted by the lenses from a 4 mm diameter monochromatic, 380, 400, or 420 nm pencil beam was collected with a 0.7 deg radius diaphragm and measured as a function of angle and of wavelength. Results: The number of fluorescent quanta was between 5% and 0.25% of that of incident quanta, dependent on age and wavelength. The dependence on wavelength of fluorescent emission was in accordance with literature. Conclusion: Because of fluorescence of the eye lens, light with wavelengths of 420 nm and below is visually much more effective than one would deduce from the CIE luminosity function. Absolute values that can be derived from fluorophotometry can be used to assess an individual's visual hindrance from short-wavelength light and other lens-related disturbances.
Keywords: 500 optical properties • 332 brightness and lightness • 338 cataract