Lens Opacities Classification System III (LOCSIII)

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Chylack LT Jr, Wolfe JK, Singer DM, et al. The Lens Opacities Classification System III. Arch Ophthalmol. 1993;111(6):831-836. doi:10.1001/archopht.1993.01090060119035

Developed by the Epidemiologic Study of Cataract Study Group, LOCS III provides standardized photographic standards to systematically evaluate four distinct types of lens opacities:

Nuclear color (NC) – Grades the color or brunescence of the nucleus from 1 (normal) to 6 (brunescent).
Nuclear opalescence (NO) – Scores the opalescence (cloudiness) of the nucleus from 1 (clear) to 6 (opaque).
Cortical (C) – Assesses the presence and extent of cortical spoking or wedge-shaped opacities, graded from 0 (none) to 5 (>90% of the lens).
Posterior subcapsular (P) – Evaluates the density and area of posterior subcapsular opacities from 0 (none) to 5 (>50% of the lens area).