Lens Opacities Classification System II (LOCS II)

TLDR

LOCS II grades nuclear, cortical, and subcapsular cataract using colored slit‑lamp and retroillumination transparencies. LOCS II employs four nuclear, five cortical, and four subcapsular standards and can be applied at the slit lamp or to photographs, offering ease of use and consistent grading across observers. The system shows very good interobserver reproducibility at the slit lamp, excellent intraobserver reproducibility, very good to excellent reproducibility of photographic gradings, and good agreement between clinical and photographic assessments, making it useful for cross‑sectional and longitudinal cataract studies.

Abstract

• The Lens Opacities Classification System, version II (LOCS II), uses a set of colored slit-lamp and retroillumination transparencies to grade different degrees of nuclear, cortical, and subcapsular cataract. The system uses four nuclear standards for grading nuclear opalescence and color, five cortical standards, and four subcapsular standards. The LOCS II can be used to grade patients' cataracts at the slit lamp or to grade slit-lamp and retroillumination photographs; it is easy to learn and can be applied consistently by different observers. We obtained very good interobserver reproducibility of the clinical gradings at the slit lamp, excellent intraobserver reproducibility, very good to excellent interobserver reproducibility of photographic gradings, and good agreement between clinical and photographic gradings. The LOCS II is potentially useful for both cross-sectional and longitudinal studies of cataract.