Considerations in the subjective assessment of cataract

The subjective classification of lens opacities is a fundamental component in both the clinical evaluation of the individual patient and in large-scale clinical trials. This procedure has been improved substantially by the implementation of standardized photographic systems depicting various levels of nuclear opacity and color, cortical, and posterior-subcapsular cataract. Comparison can also be made with recently developed objective measurements of opacity and color. Further improvements in reliability and sensitivity to change can be achieved by modifying traditional integer scaling systems by interpolating between photographic standards.