P. G. Söderberg

Evolution of light scattering after in vivo close to threshold dose of ultraviolet radiation 300 nm

Purpose: To determine the evolution of light scattering in the albino rat lens after in vivo close to threshold UVR-300 nm. n n n nMethods: Alltogether 4 groups of 20 6 weeks old albino Sprague-Dawley rats were exposed unilaterally in vivo to 8 kJ/m2 UVR-300 nm. The animals were sacrificed at 1, 7, 48 and 336 hrs after exposure after exposure to UVR, depending on group belonging and the lenses were removed for macroscopic imaging of dark-field anatomy, and quantitative measurement of intensity of forward light scattering. n n n nResults: The intensity of light scattering increased exponentially declining with a rate constant (1/k) of 71 hrs and an asymptote maximum light scattering of 0.16 tEDC. This is consistent with findings for a dose of 30 kJ/m2 although the current time constant was higher. There was an indication of a transient increase of light scattering on the contralateral side peaking at 7 hrs after expsoure. There was an indication for some repair at 336 hrs. n n n nConclusions: Light scattering evolves quicker, the higher the dose, but increases exponentially declining towards an assymptote. The current study suggest that observations of damage from close to threshold in vivo UVR exposure should be made at 1 week after exposure in order to detect the maximum damage.