KBI has established a step-wise screening system specially for monkeys by the Slit-lamp test to identify and assess cataract with the use of Lens Opacities Classification System III (LOCS III). 

As illustrated below, the color (NC) and opacity (NO) of lens nucleus are graded by comparing six color photographs of lens transections in the standard image (NO1, NC1; NO2, NC2; NO3, NC3; NO4, NC4; NO5, NC5; NO6, NC6). Posterior photography is used to compare posterior illumination color photographs to grade cortical and posterior subcapsular cataracts (C1-C5; P1~P5).