Optical performance of the bovine lens before and after cold cataract.

Cold cataracts were induced in ten bovine lenses and then removed by warming. Cataracts first appeared at an average temperature of 11.7 degrees C. The cataracts appeared to be densest at an average temperature of 1.2 degrees C, while warming caused them to disappear completely at an average temperature of 16.4 degrees C. A computer-operated scanning laser system was used to measure the equivalent focal length and changes in relative transmittance before, during, and after the cataract was induced. In general the focal length profile (spherical aberration) that existed before cooling was recaptured on warming. Scatter values indicate that transmittance is not affected by the temporary cold cataract. Thus the optical performance of the bovine lens appears to be identical before and after cold cataracts are induced. We believe that these results indicate that the cataract has a supramolecular origin.