QUANTITATING CATARACT AND NUCLEAR BRUNESCENCE, THE HARVARD AND LOCS SYSTEMS

Subjective and objective systems are used to quantify cataract at The Center for Clinical Cataract Research. We have described each system a nd its use, presented data on reproducibility and validity, and for ob jective systems, demonstrated the correlation to the subjective grade of the cataract as defined by the Lens Opacities Classification System s, Versions II and III (LOCS II and III). The subjective systems are u sed to classify nuclear color, nuclear opalescence, cortical cataract, and posterior subcapsular cataract. Reported kappa scores for LOCS II range from 0.85 to 1.0. Intraclass correlation coefficients for LOCS III (r(I)) range from 0.67 to 0.94. The computerized objective systems are: (1) fast spectral scanning colorimetry (FSSC) for assessment of nuclear color (r(I) = 0.96 to 0.98); (2) nuclear mean density (NMD) fo r assessment of nuclear opalescence (r(I) = 0.97); and (3) percent are a opacity (anterior = a; posterior = p) (OPAC-a and OPAC-p) for assess ment of cortical and posterior subcapsular cataract(r(I) = 0.92 to 0.9 6).